MANUAL
FOR THE IMPACT OF WEIGHT ON QUALITY OF LIFE (IWQOL AND IWQOL-LITE) MEASURE
Obesity and Quality of Life Consulting 762 Ninth Ninth Street #563 Durham, NC 27705 (919) 493-9995 telephone (919) 493-9925 fax www.qualityoflifeconsulting.com Ross D. Crosby, Ph.D. Neuropsychiatric Research Institute University University of o f North Dakota School of Medicine and a nd Health Sciences Fargo, North Dakota
[email protected]
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Health-Related Quality of Life (HRQOL) In its 1946 Constitution, the World Health Organization defined “health” a s “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity infirmity (1).” This T his definition of health was a departure from the old notion that health pertained only to death and disease, and it paved the way for later exploration of healthrelated quality of life. Ware, developer of the most widely widely used hea lth-related quality of life instrument (SF-36), emphasizes that health has dimensionality —physical health, mental health, everyday functioning in social and in role activities, and general perceptions of well-being—and can range from the negative negat ive states of disease to more positive states of well-being well-being (2). The terms “quality of life”, and more specifically, “health-related quality of life,” (HRQOL) are used to refer to the “physical, psychological, and social domains of health, seen as distinct areas that are influenced influenced by a person’s experiences, beliefs, expectations, and perceptions (3).” HRQOL reflects reflects an individual’s subjective evaluation and reaction to health or illness (4). Obesity and HRQOL The dramatic rise in the prevalence o f obesity worldwide has stimulated interest in the health and quality of life consequences of this phenomenon. The body of research on the quality of life of obese individuals has grown co nsiderably. Indeed, four review papers on obesity and HRQOL have been bee n written in recent years (6-9), indicating that o besity is associated with impaired quality of life in many dimensions. P opulation studies (10-12) as well as studies of obese treatment-seekers (13, 14) demonstrate a strong connection between increasing BMI and impairment in quality of life. This association association holds whether generic instruments are used to assess quality of life or whether obesity-specific instruments are used (15). In addition, weight loss has bee n associated with improvements in generic (12, 16) and obesity-specific quality of life (17, 18). History of the IWQOL The IWQOL was the first instrument specifically developed to assess the effects of the obese condition on the quality q uality of life of persons who are seeking treatment for this condition. The Impact of Weight on o n Quality of Life (IWQOL; © Duke University, 1995) questionnaire was developed in the mid-1990’s by clinicians (Ronette L. Kolotkin, Ph.D. and Michael A. Hamilton, M.D.) at an intensive treatment program for obesity, the Duke University University Diet D iet and Fitness Center. During intake interviews with patients, pat ients frequently expressed concern about and dissatisfaction with various aspects of their lives, attributing this dissatisfaction to their obesity. Complaints centered on the following following issues: health and physical functioning, social/interpersonal life, work, mobility, selfesteem, sexual life, activities of daily living, and co mfort with food. At the time of this work, the impact of obesity on physiological phys iological health was well established, but less was known about the effects e ffects of weight on psychosocial issues and daily functioning. When a literature review on quality of life issues in obesity revealed few articles on this subject and no validated instruments to assess quality quality of life in this population, it was clear that there was a need to develop an instrument to assess the impact of weight on quality quality of of life.
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Health-Related Quality of Life (HRQOL) In its 1946 Constitution, the World Health Organization defined “health” a s “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity infirmity (1).” This T his definition of health was a departure from the old notion that health pertained only to death and disease, and it paved the way for later exploration of healthrelated quality of life. Ware, developer of the most widely widely used hea lth-related quality of life instrument (SF-36), emphasizes that health has dimensionality —physical health, mental health, everyday functioning in social and in role activities, and general perceptions of well-being—and can range from the negative negat ive states of disease to more positive states of well-being well-being (2). The terms “quality of life”, and more specifically, “health-related quality of life,” (HRQOL) are used to refer to the “physical, psychological, and social domains of health, seen as distinct areas that are influenced influenced by a person’s experiences, beliefs, expectations, and perceptions (3).” HRQOL reflects reflects an individual’s subjective evaluation and reaction to health or illness (4). Obesity and HRQOL The dramatic rise in the prevalence o f obesity worldwide has stimulated interest in the health and quality of life consequences of this phenomenon. The body of research on the quality of life of obese individuals has grown co nsiderably. Indeed, four review papers on obesity and HRQOL have been bee n written in recent years (6-9), indicating that o besity is associated with impaired quality of life in many dimensions. P opulation studies (10-12) as well as studies of obese treatment-seekers (13, 14) demonstrate a strong connection between increasing BMI and impairment in quality of life. This association association holds whether generic instruments are used to assess quality of life or whether obesity-specific instruments are used (15). In addition, weight loss has bee n associated with improvements in generic (12, 16) and obesity-specific quality of life (17, 18). History of the IWQOL The IWQOL was the first instrument specifically developed to assess the effects of the obese condition on the quality q uality of life of persons who are seeking treatment for this condition. The Impact of Weight on o n Quality of Life (IWQOL; © Duke University, 1995) questionnaire was developed in the mid-1990’s by clinicians (Ronette L. Kolotkin, Ph.D. and Michael A. Hamilton, M.D.) at an intensive treatment program for obesity, the Duke University University Diet D iet and Fitness Center. During intake interviews with patients, pat ients frequently expressed concern about and dissatisfaction with various aspects of their lives, attributing this dissatisfaction to their obesity. Complaints centered on the following following issues: health and physical functioning, social/interpersonal life, work, mobility, selfesteem, sexual life, activities of daily living, and co mfort with food. At the time of this work, the impact of obesity on physiological phys iological health was well established, but less was known about the effects e ffects of weight on psychosocial issues and daily functioning. When a literature review on quality of life issues in obesity revealed few articles on this subject and no validated instruments to assess quality quality of life in this population, it was clear that there was a need to develop an instrument to assess the impact of weight on quality quality of of life.
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Since the time of the initial initial development develop ment of the IWQOL, interest in the quality of life o f obese persons has grown considerably. In June o f 1999 the North American Association Assoc iation for the Study of Obesity convened a task force--Task Force on Developing Obesity Outcomes and Learning Tools (TOOLS)--whose charge was to choose outcome measures to be used by obesity o besity clinicians and researchers (19). The task force recommended t he use of the IWQOL-Lite (a short-form of the IWQOL that will be described in deta il later) in clinical practice and in research studies stud ies on obesity.
Item Develop Develop ment o f t he IWQO IWQOL L Items for the IWQOL reflected the most commonly expressed concerns by pat ients in treatment for obesity. Patients (individually and in group s) were asked to describe the effects of being overweight in their everyday lives. Their responses were recorded, rewritten in the form of items, and grouped by category. In addition, clinicians who specialized in the treatment of obese persons wrot e and categorized items based on t heir clinical experience. Items were tested for clarity and modified as needed. The result of of this process was a 74-item IWQOL questionnaire, with 14 items relating to ph ysical health, 11 relating to social/in so cial/interpersonal terpersonal life, 7 relating to work, 10 relating to mobility, 10 relating to self-esteem, 6 relating to sexual life, life, 7 relating to activities of daily living, and 9 relating to comfort with food. Scores for each scale were co mputed by summing scores on individual items, with 1=”never true” and 5=”always true.” With the exception of the Comfort With Food scale, the higher h igher the score, the poorer the qua lity lity of o f life in that area. The initial publication on the IWQOL consisted of two studies: one dealing with item development, reliability, and treatment effects on a small sample of 64 patients, the other dealing with the relationship between BMI, age, and gender on quali qua lity ty of o f life in 181 patients (20). The IWQOL in Clinical Trials IWQOL and SF-36 data from four randomized c linical trials for for sibutramine versus placebo in mildly to moderately obese patients were analyzed in order to determine the effects of moderate weight loss on health-related quality of life(18). After approximately 6-months of treatment, statistically significant relationships were o bserved between weight change and IWQOL scores for the following scales: Health, Social/Interpersonal, Mobility, Self-Esteem, Activities Activities of Daily Living, and total score of the IWQOL. For the t he SF-36, statistically significant relationships were observed for Physical Function, General Health Perception, Pain, Vitality, and Emotional Ro le. Weight reduction of between 5 and 10 percent was associated assoc iated with an effect size of .29 IWQOL total score po ints. IWQOL scales showing the greatest sensitivity to change were Hea lth, Mobility, Mobility, and total tot al score. See Bibliography for other studies using the IWQOL. Development of the Short-Form: IWQOL-Lite Because the IWQOL contained a large number of items (74 items), researchers designing clinical trials for obesity expressed concern about the po tential for response burden to subjects. As a result, a shorter version was developed, t he IWQOL-Lite. The objectives in developing a short-form were as follows: 1) to assess obesity-specific quality of life in a brief version version that is convenient to use, and 2) to improve upon the psychometric properties of the IWQOL. Having achieved these objectives, we no longer recommend
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use of the IWQOL long form. If you have used the long form in your data collection, you may still score it using IWQOL-Lite scoring scoring criteria. See the section on scoring the IWQOL-Lite.
Item Selection Process(13)
We analyzed baseline IWQOL data from 1,987 subjects who had taken the t he IWQOL in a variety of settings –an open label study of phentermine-fenfluramine, an intensive daytreatment program, an outpatient weight loss treatment program, gastric bypass surgery, and community volunteers. The sample was randomly divided into two groups: a Development Sample (N = 996) 99 6) and a Cross-Validation Sample (N=991). The Development Sample and the Cross-Vali Cro ss-Validation dation Sample were not statistically different from each other in terms of BMI, age, gender, or race (p>.25). The Development Sample provided data upon which decisions about item selection and scale construction were based. Selection of items and construction of scales in the Development Development Sample S ample was accomplished by compiling data on each of the 74 original IWQOL items. items. Data included frequency distributions, inter-item correlations, alpha coe fficients fficients for scales and total score, item-to-scale correlations for scales and total score, baseline correlations with collateral measures, exploratory factor analysis, and 1-year change co rrelations between items and collateral measures. Items were selected if they adequat ely distributed across item responses (“never true” to “always true”), maximized a lpha coefficients, maximized item-to-scale correlations, correlations, and correlated significantly with relevant collateral measures, both cross-sectionally and longitudinally. longitudinally. Initially, we deleted items from the original 74 if they (1) correlated poorly with the scale score, (2) correlated poorly with the total score, or (3) correlated poorly with BMI. Changes in items at one-year follow-up were then correlated with changes in BMI at one-year follow-up. Additional items were deleted if they did not correlate well with changes in BMI. Exploratory factor analyses were then performed on the reduced set of items. Factor loadings were examined, and additional items were deleted if they did no t load adequately on t he derived factors. This process was repeated iteratively until an acceptable and interpretable factor structure was obtained. Therefore, assignment of items items to scales was based both both on exploratory factor analysis and on the original original scale composition. All decisions decisions about item selection were finalized prior to analyzing any data in the Cross-Validation Cross-Validation Sample. Methods Used in the Psychometric Evaluation of the IWQOL-Lite (13)
Psychometric evaluation was based entirely on t he Cross-Validation Sample. Using the Cross-Validation Sample, a two-way analysis of variance (ANOVA) was performed for each of the newly developed de veloped scales and total score distrib d istributed uted across 5 BMI classifications (< 25, 25-29.9, 30-34.9, 35-39.9, 40+) by gender. An alpha of .01 was used to control for for multiple comparisons. Post hoc tests for for comparisons between BMI groups were performed using Tukey’s honestly significant difference method (hsd) based on an alpha of .01.
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A series of confirmatory factor analyses was performed on t he Cross-Validation Cross-Validation Sample to evaluate the hypothesized hypot hesized scale structure using EQS software. The sensitivity of the IWQOL-Lite was evaluated on the Cro ss-Validation ss-Validation Sample using two different methods. First, effect sizes were calculated between adjacent BMI groups (< 25 vs. 25-29.9, 25.9-29.9 vs. 30-34.9, 30-34.9 vs. 35-39.9, etc.) and between extreme BMI groups (<25 vs. 40+). Effect sizes were calculated as the difference between group means (after adjusting for age and gender) d ivided by the standard deviation for the entire sample. For example, the effect size co mparing <25 with 40+ would be calculated as the adjusted mean for <25 minus the adjusted mean for 40+. That quantity is the n divided by the standard deviation for the entire group. grou p. Next, effect sizes were calculated in the o ne year longitudinal sample (N = 160) for 3 groups: (1) those subjects losing less than 10% of baseline BMI, (2) those subjects losing 10-20% o f their baseline BMI, and (3) those subjects losing more more than 20% of their baseline baseline BMI. Effect sizes were calculated as the difference between IWQOL-Lite scores at baseline and 1 year (after adjusting for age and gender) divided by the standard deviation de viation at baseline (32). Effect sizes were calculated instead of Guyatt’s responsiveness statistic because there were not sufficient cases with stable weight over the one-year o ne-year period (97% lost at least 10 pounds and 89 % lost at least 20 pounds, leaving only five subjects who lost less than ten pounds.) po unds.) Characteristics of the IWQOL-Lite 31 items Items begin with the phrase, “Because of o f my weight…” 5 domains o physical function (11 items) o self-esteem (7items) o sexual life (4 items) o public distress (5 items) items) o work (4 items) Total score Each item has 5 response options op tions (1= “never true,” 2=”rarely true,” 3=”sometimes true,” 4=”usually true,” and 5=”always true.”) • • •
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Administration of the IWQOL-Lite Administration of the IWQOL-Lite is easy a nd respondents seldom have difficulty understanding the instructions. Due to the sensitive nature o f some of the items, respondents may prefer to leave a few items blank. Generally, this does not affect the scoring (see scoring algorithm below). It is acceptable for people to omit items, unless it is careless omission of items. It is recommended that ad ministering ministering staff say something like, "I need to check to see that you didn't accidentally omit any items. Is this okay with you? Did you o mit mit any items intentionally?" If they say that they t hey omitted items intentionally, then perhaps staff does not check this person's form for omitted items, OR perhaps instead the staff asks the subject to identify in in which section(s) intentionally omitted items occurred. Then the research staff can c heck to see that there t here were not any accidentally missed items in the other sections, asking them, "is it okay if I look for accidentally missed items in the other sections?"
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Meaningful Change in IWQOL-Lite Scores Meaningful changes in IWQOL-Lite total score are det ermined using the algorithm described by Crosby and colleagues (21, 22). Based on this algorithm, patients’ IWQOLLite total scores are considered to have shown meaningful improvement from baseline to one year if they increased between 7 and 12 points, depending upon baseline severity in comparison to the normative mean. Normative means for the IWQOL-Lite have been derived from a sample of 534 non-obese individuals who were not enrolled in any weight loss treatment program [238 women and 296 men with BMI’s between 18.5 and 29.9] (21). Available Languages for the IWQOL-Lite
Afrikaans for South Africa, Arabic for UAE (United Arabic Emirates), Arabic for Israel, Bengali for India, Bulgarian for Bulgaria, Cata lan for Spain, Chinese for Hong Kong, Chinese for Taiwan, Cebuano for Philippines, Chinese for Hong Kong, Chinese for Taiwan, Czech for Czech Republic, Danish for Denmark, Dutch for Netherlands, Dut ch for Belgium, English for Australia, English for Canada, English for Ind ia, English for Malaysia, English for New Zealand, English for Philippines, English for S ingapore, English for South Africa, English for the UK ( including Ireland), English for the US, Estonian for Estonia, Finnish for Finland, French fo r France, French for Belgium, French for Canada, French for Switzerland, German for Germany, German for Austria, German for Switzerland, Greek for Greece, Gujarati for India, Harmonized Lat in American and U.S. Spanish, Hebrew for Israel, Hindi for India, Hungarian for Hungary, Italian for Italy, Italian for Switzerland, Japanese for Japan, Kannada for India, Korean for Korea, Latvian for Latvia, Lithuanian for Lithuania, Malay for Malaysia, Malay for Singapore, Malayalam for India, Mandarin for Malaysia, Mandarin for S ingapore, Marathi for India, Norwegian for Norway, Polish for Poland, Portuguese for Portugal, Portuguese for Brazil, Romanian for Romania, Russian for Russia, Russian for Israel, Russian for Estonia, Russian for Latvia, Russian for Ukraine, Slovakian for Slovakia, Spanish for Spain, Spanish for Argentina, Spanish for Chile, S panish for Costa Rica, Spanish for Mexico, Spanish for Peru, Spanish for Puerto Rico, Spanish for the USA, Swed ish for Sweden, Swedish for Finland, Tagalog for Philippines, Tamil for India, Tamil for Malaysia, Telugu for India, Thai for Thailand, T urkish for Turkey, Ukrainian for Ukraine, Urdu for India, Xhosa for South Africa, and Zulu for South Africa. Six-Month Changes in IWQOL-Lite Scores for Weight Loss Participants (n = 4511) Data from 10 non-surgical weight loss studies were poo led to examine six-month changes in IWQOL-Lite scores by weight loss/gain category (weight gain, 0-4.9% loss, 5-9.9% loss, 10-14.9% loss, and 15+% loss). In Figures 1- 6 mean IWQOL-Lite change scores by gender are displayed. In Tables 11-13 means and standard deviations are displayed for each weight loss/gain category for men, women, and the total sample. Ceiling and Floor Effects of the IWQOL-Lite (Based on a sample size of 12,231 (which includes 550 nonobese, 1344 overweight, 3371 with a BMI of 30-34.9, 3109 with a BMI of 35-39.9, and 3857 with a BMI of 40+)
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Ceiling Effects 2% of all individuals scored at the ceiling (a score of 100, i.e. no impairment) on the IWQOL-Lite For adults with obesity (BMI 30 and above), .5% scored at the ceiling For adults with a BMI between 30-34.9, .9% scored at the ceiling For adults with a BMI between 35-39.9, .5% scored at the ceiling For adults with a BMI 40 and above, .1% scored at the ceiling For adults with overweight/obesity (BMI 25 and above), 1 % scored at the ceiling • • •
Floor Effects .1% of all individuals scored at the floor (a score of 0, i.e. the most severe impairment) on the IWQOL-Lite For adults with obesity (BMI 30 and above), .1% scored at the floor For adults with a BMI between 30-34.9, .0% scored at the floor For adults with a BMI between 35-39.9, .0% scored at the floor For adults with a BMI 40 and above, .3% scored at the floor For adults with overweight/obesity (BMI 25 and above), .1% scored at the floor • • •
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Below are tables describing the psychometric properties of the IWQOL-Lite in different samples. Tables 2-9 are based on data from over 11,000 subjects.
Table 1. Test-retest reliabil ity of th e IWQOL-Lite Community Psychiatric 1 Sample Sample2 Test-Retest ICC Test-Retest ICC IWQOL-Lite Scale (n = 112 ) (n = 65 ) Physical Function .877 .862 Self-Esteem
.870
.864
Sexual Life
.849
.764
Public Distress
.814
.938
Work
.857
.840
Total Score
.937
.935
1 Kolotkin R L, Crosby R D. Psychometric evaluation of the Impact Of W eight On Quality Of Life-Lite Questionnaire (IWQOL-Lite) in a community sample. Quality of Life Research 2002; 11: 157-171. 2 Kolotkin R L, Crosby R D, Corey-Lisle P K, Li H, Swanson J M. Performance of a weight-related measure of quality of lif e in a psychiatric sample. Quality of Life Research 2006; 15:587-596.
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Table 2. Demographic and Weight General Severely Community Obese Community (n = 711 )
Characteristics of Samples Weight Outpatient Residential Loss Weight Weight Clinical Loss Loss Trials Program Program
(n = 317)
Psychiatric
Obese With Type 2 Diabetes
Obese With BED
(n = 209 )
(n = 692 )
(n = 95 )
Obese with Hyperlipidemia
(n = 1635) (n = 5519)
Female (n, %) Age (mean, SD) Caucasian (n, %) BMI (mean, SD) BMI Group (n %) 18-24.9 25-29.9 30-34.9 35-39.9 40+
Bariatric Surgery
401 (56.4)
241 (76.0)
3971 (72.0)
37.6 (12.4)
48.8 (10.9)
47.0 (11.4)
442 (62.2)
308 (97.2)
4398 (79.7)
27.4 (6.8)
43.2 (6.3)
286 (40.2) 248 (34.9) 104 (14.6) 45 (6.3%) 28 (3.9)
0 (0) 0 (0) 7 (2.2) 93 (29.3) 217 (68.5)
(n = 2250) 1827 (81.2) 45.4 (11.3)
(n = 736) 439 (59.6)
1345 (82.3)
112 (53.6)
330 (47.7)
72 (75.8)
(n = 850) 505 (59.4)
49.3 (13.6)
42.3 (10.7)
43.1 (10.7)
55.2 (9.3)
45.0 (12.6)
47.2 (10.6)
674 (91.6)
146 (69.9)
550 (79.5)
94 (98.9)
773 (90.9)
33.8 (8.6)
34.5 (3.8)
42.0 (10.3)
34.3 (4.6)
33 (15.8) 38 (18.2) 61 (29.2) 35 (16.7) 42 (20.1)
4 (0.6) 96 (13.9) 257 (37.1) 297 (42.9) 38 (5.5)
0 (0) 8 (8.4) 13 (13.7) 19 (20.0) 55 (57.9)
0 (0) 152 (17.9) 355 (41.8) 266 (31.3) 77 (9.1)
36.8 (6.0)
1318 (81.7%)1 36.5 (6.7)
39.3 (10.0)
1242 (90.2)2 47.5 (8.4)
4 (0.1) 402 (7.3) 2009 (36.4) 1824 (33.0) 1280 (23.2)
0 (0) 272 (12.1) 804 (35.7) 634 (28.2) 539 (24.0)
0 (0) 99 (13.5) 190 (25.8) 159 (21.6) 288 (39.1)
0 (0) 0 (0) 21 (1.3) 216 (13.2) 1398 (85.5)
1
of 1613 reporting ethnicity
2
of 1377 reporting ethnicity
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Table 3. IWQOL-Lite Correlations with BMI for Different Samples IWQOLGeneral Severely Weight Outpatient Residential Lite Scale Community Obese Loss Weight Weight Community Clinical Loss Loss Trials Program Program (n = 711 ) (n = 317) (n = (n = 2250) 5519) (n = 736) Physical -.605*** -.440*** -.402*** -.422*** -.570*** Function
Bariatric Surgery
Psychiatric
Obese With Type 2 Diabetes
Obese With BED
Obese with Hyperlipidemia
(n = 209 )
(n = 692 )
(n = 95 )
(n = 850)
-.252***
-.617***
-.313***
-.498***
-.339***
(n = 1635)
SelfEsteem
-.315***
-.127*
-.190***
-.179***
-293***
.048
-.540***
-.278***
-.164
-.191***
Sexual Life
-.242***
-.116*
-.130***
-.166***
-.204***
-.034
-.390***
-.153***
-.133
-.150***
Public Distress
-.460***
-.506***
-.571***
-.548***
-.699***
-.382***
-.593***
-.351***
-.643***
-.519***
Work
-.413***
-.240***
-.220***
-.304***
-.266***
-.195***
-.563***
-.211***
-.251*
-.225***
Total Score
-.534***
-.376***
-.389***
-.409***
-.569***
-.215***
-.649***
-.337***
-.469***
-.349***
Table 3. IWQOL-Lite Correlations with BMI for Different Samples IWQOLGeneral Severely Weight Outpatient Residential Lite Scale Community Obese Loss Weight Weight Community Clinical Loss Loss Trials Program Program (n = 711 ) (n = 317) (n = (n = 2250) 5519) (n = 736) Physical -.605*** -.440*** -.402*** -.422*** -.570*** Function
Bariatric Surgery
Psychiatric
Obese With Type 2 Diabetes
Obese With BED
Obese with Hyperlipidemia
(n = 209 )
(n = 692 )
(n = 95 )
(n = 850)
-.252***
-.617***
-.313***
-.498***
-.339***
(n = 1635)
SelfEsteem
-.315***
-.127*
-.190***
-.179***
-293***
.048
-.540***
-.278***
-.164
-.191***
Sexual Life
-.242***
-.116*
-.130***
-.166***
-.204***
-.034
-.390***
-.153***
-.133
-.150***
Public Distress
-.460***
-.506***
-.571***
-.548***
-.699***
-.382***
-.593***
-.351***
-.643***
-.519***
Work
-.413***
-.240***
-.220***
-.304***
-.266***
-.195***
-.563***
-.211***
-.251*
-.225***
Total Score
-.534***
-.376***
-.389***
-.409***
-.569***
-.215***
-.649***
-.337***
-.469***
-.349***
Obese With Type 2 Diabetes
Obese With BED
Obese with Hyperlipidemia
(n = 692 )
(n = 95 )
(n = 850)
72.1 (20.1)
49.7 (28.2)
73.2 (19.0)
* p < .05 ** p < .01 *** p < .001
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Table 4.Means and Standard Deviations of IWQOL-Lite Scor es for Diff erent Samples IWQOLGeneral Severely Weight Outpatient Residential Bariatric Psychiatric Lite Scale Community Obese Loss Weight Weight Surgery Community Clinical Loss Loss Trials Program Program (n = 711 ) (n = 317) (n = (n = 1635) 5519) (n = 2250) (n = 209 ) (n = 736) Physical 90.0 (14.9) 48.4 (21.2) 68.9 65.1 (22.2) 57.3 (26.4) 31.7 62.6 Function (20.6) (21.7) (27.5) SelfEsteem
87.5 (19.4)
45.9 (25.9)
59.1 (26.4)
56.1 (27.7)
57.7 (27.2)
30.4 (25.3)
57.2 (31.4)
72.0 (24.7)
39.3 (25.9)
63.6 (26.0)
Sexual Life
95.1 (13.0)
65.9 (29.9)
75.1 (26.0)
70.9 (28.0)
65.8 (28.2)
45.8 (31.8)
66.7 (34.6)
80.5 (23.6)
59.1 (30.4)
79.1 (24.5)
Public Distress
96.5 (10.9)
62.0 (24.7)
83.5 (20.2)
78.9 (23.6)
71.8 (26.7)
40.8 (25.4)
75.5 (27.4)
89.1 (16.1)
59.2 (28.4)
88.8 (15.7)
Work
95.4 (11.5)
68.1 (23.7)
79.7 (21.9)
72.0 (23.5)
54.6 (19.5)
67.9 (19.6)
62.6 (20.7)
72.2 (28.9) 65.3 (25.2)
60.8 (28.9) 51.5 (21.9)
85.4 (17.3)
91.8 (12.0)
49.7 (27.5) 36.9 (19.0)
85.6 (18.0)
Total Score
84.0 (18.4) 71.8 (17.8)
77.6 (16.8)
75.9 (16.3)
Table 4.Means and Standard Deviations of IWQOL-Lite Scor es for Diff erent Samples IWQOLGeneral Severely Weight Outpatient Residential Bariatric Psychiatric Lite Scale Community Obese Loss Weight Weight Surgery Community Clinical Loss Loss Trials Program Program (n = 711 ) (n = 317) (n = (n = 1635) 5519) (n = 2250) (n = 209 ) (n = 736) Physical 90.0 (14.9) 48.4 (21.2) 68.9 65.1 (22.2) 57.3 (26.4) 31.7 62.6 Function (20.6) (21.7) (27.5)
Obese With Type 2 Diabetes
Obese With BED
Obese with Hyperlipidemia
(n = 692 )
(n = 95 )
(n = 850)
72.1 (20.1)
49.7 (28.2)
73.2 (19.0)
SelfEsteem
87.5 (19.4)
45.9 (25.9)
59.1 (26.4)
56.1 (27.7)
57.7 (27.2)
30.4 (25.3)
57.2 (31.4)
72.0 (24.7)
39.3 (25.9)
63.6 (26.0)
Sexual Life
95.1 (13.0)
65.9 (29.9)
75.1 (26.0)
70.9 (28.0)
65.8 (28.2)
45.8 (31.8)
66.7 (34.6)
80.5 (23.6)
59.1 (30.4)
79.1 (24.5)
Public Distress
96.5 (10.9)
62.0 (24.7)
83.5 (20.2)
78.9 (23.6)
71.8 (26.7)
40.8 (25.4)
75.5 (27.4)
89.1 (16.1)
59.2 (28.4)
88.8 (15.7)
Work
95.4 (11.5)
68.1 (23.7)
79.7 (21.9)
72.0 (23.5)
54.6 (19.5)
67.9 (19.6)
62.6 (20.7)
72.2 (28.9) 65.3 (25.2)
60.8 (28.9) 51.5 (21.9)
85.4 (17.3)
91.8 (12.0)
49.7 (27.5) 36.9 (19.0)
85.6 (18.0)
Total Score
84.0 (18.4) 71.8 (17.8)
77.6 (16.8)
75.9 (16.3)
11
Table 5. Means and Standard Deviations of IWQOL-Lite Scores by BMI and Gender for Total Sample (n = 11,640) BMI IWQOL scale
Physical Function
Self-Esteem
Sex
18.0-24.9
25–29.9
30–34.9
35–39.9
40+
Females
94.8 (7.3) n = 241
82.0 (15.0) n = 758
71.8 (19.1) n = 2338
61.9 (22.0) n = 2212
43.9 (24.6) n = 2924
Males
93.8 (11.0) n = 97
88.8 (11.0) n = 441
78.1 (17.4) n = 945
67.6 (20.6) n = 810
46.2 (25.7) n = 870
Total
94.5 (8.5) n = 338
84.4 (14.1) n = 1199
73.6 (18.8) n = 3283
63.4 (21.8) n = 3022
44.5 (24.9) n = 3794
Females
85.5 (20.1) n = 241
65.0 (26.0) n = 758
55.4 (26.4) n = 2338
49.3 (26.7) n = 2213
40.1 (27.2) n = 2924
Males
95.0 (12.6) n = 97)
87.9 (16.1) n = 440
77.4 (20.7) n = 944
68.3 (24.0) n = 809
53.1 (27.4) n = 870
Total
88.2 (18.8) n = 338
73.4 (25.4) n = 1198
61.8 (26.8) n = 3282
54.4 (27.3) n = 3022
43.1 (27.8) n = 3794
Table 5. Means and Standard Deviations of IWQOL-Lite Scores by BMI and Gender for Total Sample (n = 11,640) BMI IWQOL scale
Physical Function
Self-Esteem
Sexual Life
Public Distress
Work
IWQOL-Lite Total
Sex
18.0-24.9
25–29.9
30–34.9
35–39.9
40+
Females
94.8 (7.3) n = 241
82.0 (15.0) n = 758
71.8 (19.1) n = 2338
61.9 (22.0) n = 2212
43.9 (24.6) n = 2924
Males
93.8 (11.0) n = 97
88.8 (11.0) n = 441
78.1 (17.4) n = 945
67.6 (20.6) n = 810
46.2 (25.7) n = 870
Total
94.5 (8.5) n = 338
84.4 (14.1) n = 1199
73.6 (18.8) n = 3283
63.4 (21.8) n = 3022
44.5 (24.9) n = 3794
Females
85.5 (20.1) n = 241
65.0 (26.0) n = 758
55.4 (26.4) n = 2338
49.3 (26.7) n = 2213
40.1 (27.2) n = 2924
Males
95.0 (12.6) n = 97)
87.9 (16.1) n = 440
77.4 (20.7) n = 944
68.3 (24.0) n = 809
53.1 (27.4) n = 870
Total
88.2 (18.8) n = 338
73.4 (25.4) n = 1198
61.8 (26.8) n = 3282
54.4 (27.3) n = 3022
43.1 (27.8) n = 3794
Females
94.5 (14.4) n = 237
78.6 (24.8) n = 735
71.3 (27.3) n = 2250
67.3 (28.6) n = 2134
57.6 (32.6) n = 2750
Males
97.7 (10.9) n = 97
94.3 (13.0) n = 439
86.3 (19.3) n = 939
80.5 (22.9) n = 807
66.1 (29.6) n = 849
Total
95.4 (13.5) n = 334
84.5 (22.5) n = 1174
75.7 (26.1) n = 3189
70.9 (27.8) n = 2941
59.6 (32.1) n = 3599
Females
97.8 (8.1) n = 241
94.9 (10.2) n = 758
89.3 (15.0) n = 2338
78.2 (21.2) n = 2211
51.9 (27.9) n = 2925
Males
97.3 (10.9) n = 97
97.3 (6.8) n = 441
93.2 (11.1) n = 944
84.5 (17.5) n = 810
55.7 (27.4) n = 870
Total
97.7 (9.0) n = 338
95.8 (9.2) n = 1199
90.4 (14.1) n = 3282
79.9 (20.4) n = 3021
52.8 (27.8) n = 3795
Females
97.6 (8.3) n = 234
89.1 (16.3) n = 747
84.2 (18.8) n = 2322
77.6 (22.4) n = 2182
63.7 (28.4) n = 2877
Males
96.7 (9.9) n = 94
93.3 (12.6) n = 436
88.5 (15.1) n = 934
83.4 (18.5) n = 798
67.7 (26.3) n = 854
Total
97.4 (8.7) n = 328
90.7 (15.2) n = 1183
85.4 (17.9) n = 3256
79.1 (21.6) n = 2980
64.6 (28.0) n = 3731
Females
93.5 (8.8) n = 241
80.7 (13.8) n = 758
72.5 (16.6) n = 2339
64.4 (19.1) n = 2213
48.5 (22.3) n = 2925
Males
95.5 (10.0) n = 97
91.3 (9.1) n = 441
82.8 (13.4) n = 945
74.2 (16.4) n = 810
54.6 (22.1) n = 870
Total
94.0 (9.2) n = 338
84.6 (13.3) n = 1199
75.4 (16.5) n = 3284
67.0 (18.9) n = 3023
49.9 (22.4) n = 3795
12
Table 6. Means and Standard Deviations of IWQOL-Lite Scores by Age and Gender for Obese Sample (BMI > 30) (n = 10,096) Age Group IWQOL scale
Physical Function
SelfEsteem
Sexual Life
Public Distress
Work
IWQOLLite Total
Sex
18.0-24.9
25–34.9
35–44.9
45–54.9
55-64.9
65+
Females
65.9 (24.8) 60.3 (24.9) 59.1 (25.1) 56.4 (24.8) 55.1 (26.0) 56.2 (24.4) n = 303 n = 1245 n = 2068 n = 2322 n = 1232 n = 301
Males
73.6 (21.3) 69.2 (23.0) 63.9 (25.4) 62.4 (26.2) 62.5 (25.1) 69.1 (23.5) n = 50 n = 294 n = 615 n = 852 n = 630 n = 181
Total
67.0 (24.5) 62.0 (24.8) 60.2 (25.2) 58.0 (25.3) 57.6 (25.9) 61.1 (24.8) n = 353 n = 1539 n = 2683 n = 3174 n = 1862 n = 482
Females
44.6 (27.4) 40.1 (27.1) 44.6 (27.3) 49.7 (26.6) 54.0 (27.8) 60.4 (25.4) n = 302 n = 1245 n = 2070 n = 2321 n = 1233 n = 301
Males
57.5 (26.8) 60.3 (28.1) 61.6 (26.2) 65.9 (26.1) 71.7 (24.2) 80.6 (20.2) n = 49 n = 293 n = 615 n = 852 n = 630 n = 181
Total
46.4 (27.6) 44.0 (28.4) 48.5 (28.0) 54.0 (27.4) 60.0 (27.9) 70.0 (25.5) n = 351 n = 1538 n = 2685 n = 3173 n = 1863 n = 482
Females
73.3 (27.6) 64.0 (30.3) 64.3 (29.5) 64.6 (30.5) 64.1 (31.9) 67.9 (31.0) n = 291 n = 1212 n = 2022 n = 2230 n = 1123 n = 253
Males
84.3 (24.9) 80.8 (24.8) 79.7 (25.7) 77.2 (25.3) 75.1 (26.2) 77.7 (25.4) n = 47 n = 294 n = 609 n = 843 n = 621 n = 178
Total
74.8 (27.4) 67.3 (30.1) 67.9 (29.4) 68.1 (29.7) 68.0 (30.5) 72.0 (29.2) n = 338 n = 1506 n = 2631 n = 3073 n = 1744 n = 431
Females
68.6 (28.6) 64.8 (29.3) 69.3 (28.2) 73.1 (26.7) 76.7 (26.3) 81.1 (22.1) n = 303 n = 1245 n = 2069 n = 2321 n = 1232 n = 301
Males
77.0 (24.6) 73.8 (26.8) 74.0 (27.9) 77.2 (25.9) 82.2 (22.2) 89.3 (17.1) n = 50 n = 293 n = 615 n = 852 n = 630 n = 181
Total
69.8 (28.2) 66.5 (29.0) 70.3 (28.2) 74.2 (26.5) 78.5 (25.1) 84.2 (20.7) n = 353 n = 1538 n = 2684 n = 3173 n = 1862 n = 482
Females
77.4 (26.4) 72.9 (26.4) 73.5 (26.0) 75.1 (24.9) 74.6 (25.4) 74.3 (22.2) n = 300 n = 1230 n = 2050 n = 2294 n = 1212 n = 292
Males
81.4 (19.5) 79.1 (22.9) 78.2 (24.9) 79.2 (22.8) 81.7 (19.5) 85.5 (17.4) n = 50 n = 292 n = 606 n = 844 n = 616 n = 175
Total
77.9 (25.5) 74.1 (25.9) 74.6 (25.8) 76.2 (24.4) 77.0 (23.9) 78.5 (21.2) n = 350 n = 1522 n = 2656 n = 3138 n = 1828 n = 467
Females
63.9 (21.9) 58.5 (22.4) 60.0 (22.4) 61.0 (21.9) 61.9 (22.8) 64.7 (19.9) n = 303 n = 1245 n = 2070 n = 2323 n = 1233 n = 300
Males
73.0 (16.4) 70.7 (21.4) 68.8 (22.3) 69.6 (21.8) 71.8 (20.4) 78.2 (17.1) n = 50 n = 294 n = 615 n = 852 n = 630 n = 181
Total
65.2 (21.4) 60.8 (22.7) 62.0 (22.6) 63.3 (22.2) 65.3 (22.5) 70.0 (20.0) n = 353 n = 1539 n = 2685 n = 3175 n = 1863 n = 481
13
Table 7. Cut-offs fo r no ne, mild, mod erate, severe baseline IWQOL-Lite tot al score* IWQOL-Lite None Mild Moderate Severe Total Score = > 87.1. 79.5-87.0 71.9-79.4 <71.9 *Based on Crosby, R. D., Kolotkin, R. L., & Williams, G. R. (2004). An integrated method to determine meaningful changes in health-related quality of life. J Clin Epidemiol, 57(11), 1153-1160. (Normative sample = 534 normal/overweight individuals not enrolled in a weight loss program)
14
Table 8. Item to Scale Correlations Total Sample (n = 11,640) Physical SelfSexual
Public
Function
Esteem
Life
Distress
Work
Total
Picking up objects
-.808
-.480
-.477
-.577
-.554
-.721
Tying shoes
-.811
-.472
-.470
-.577
-.540
-.715
Getting up from chairs
-.845
-.497
-.501
-.646
-.596
-.762
Using stairs
-.834
-.518
-.495
-.632
-.585
-.759
Dressing
-.750
-.451
-.491
-.569
-.587
-.695
Mobility
-.816
-.487
-.504
-.635
-.635
-.752
Crossing legs
-.742
-.523
-.460
-.633
-.518
-.714
Feel short of breath
-.747
-.500
-.465
-.558
-.544
-.696
Painful stiff joints
-.634
-.377
-.371
-.435
-.439
-.558
Swollen ankles/legs
-.627
-.398
-.403
-.494
-.477
-.589
Worried about health
-.568
-.506
-.390
-.486
-.456
-.596
Self-conscious
.-.495
-.794
-.475
-.482
-.427
-.650
Self-esteem not what it
-.516
-.844
-.518
-.502
-.491
-.692
Unsure of self
-.530
-.855
-.545
-.546
-.555
-.724
Do not like myself
-.477
-.805
-.547
-.482
-.506
-.669
Afraid of rejection
-.500
-.799
-.533
-.600
-.558
-.708
Avoid looking in mirrors
-.509
-.754
-.529
-.518
-.475
-.671
Embarrassed in public
-.573
-.767
-.592
-.639
-.617
-.761
Physical Function
Self-Esteem
could be
15
Sexual Life -.508
-.598
-.856
-.480
-.530
-.669
Little sexual desire
-.499
-.548
-.855
-.434
-.505
-.637
Difficulty with sexual
-.603
-.558
-.810
-.547
-.579
-.713
-.498
-.571
-.862
-.475
-.530
-.653
Experience ridicule
-.508
-.547
-.439
-.669
-.579
-.645
Fitting in public seats
-.683
-.548
-.466
-.854
-.587
-.740
Fitting through aisles
-.687
-.569
-.486
-.872
-.601
-.757
Worry about finding chairs
-.668
-.512
-.461
-.847
-.600
-.722
Experience discrimination
-.551
-.562
-.454
-.731
-.628
-.684
-.630
-.504
-.521
-.584
-.772
-.694
Less productive
-.624
-.526
-.504
-.542
-.712
-.680
Do not receive recognition
-.482
-.423
-.442
-.561
-.685
-.585
Afraid to go on interviews
-.545
-.577
-.512
-.636
-.674
-.678
Do not enjoy sexual activity
performance Avoid sexual encounters
Public Distress
Work Trouble accomplishing things
Bold cells represent correlations corrected for influence of that item
16
Table 9. Internal Consistency of IWQOL-Lite Scores for Different Samples IWQOLGeneral Severely Weight Outpatient Residential Bariatric Lite Community Obese Loss Weight Weight Surgery Scale Community Clinical Loss Loss Trials Program Program (n = 711 ) (n = 317) (n = (n = 5519) (n = 2250) 1635) (n = 736)
Psychiatric
Obese With Type 2 Diabetes
Obese With BED
Obese with Hyperlipidemia
Total
(n = 209 )
(n = 692 )
(n = 95 )
(n = 850)
Physical Function
.920
.908
.908
.906
.935
.908
.9 39
.910
.945
.893
(n = 11,640) .940
SelfEsteem
.938
.935
.927
.928
.922
.920
.9 45
.932
.912
.926
.940
Sexual Life
.910
.939
.926
.923
.890
.927
.9 32
.909
.893
.925
.935
Public Distress
.893
.881
.889
.888
.893
.861
.9 13
.872
.875
.844
.919
Work
.831
.795
.789
.836
.882
.800
.892
.781
.913
.770
.860
Total Score
.953
.949
.951
.952
.953
.941
.9 73
.953
.955
.945
.967
17
Table 10a. Percenti les Ass ociated wi th IWQOL-Lite Scor es for Obese Female Sample (BMI > 30) (n = 7,478)
Percentiles
1 2 3 4 5 6 7 8 9 10
Physical Function .000 4.545 6.818 9.091 11.364 13.636 15.909 15.909 18.182 20.455
SelfEsteem .000 .000 .000 .000 3.571 3.571 3.571 7.143 7.143 10.714
Sexual Life .000 .000 .000 .000 .000 6.250 6.250 12.500 12.500 18.750
Public Distress .000 5.000 10.000 15.000 15.000 20.000 20.000 25.000 25.000 30.000
Work .000 6.250 12.500 18.750 25.000 25.000 31.250 31.250 31.250 37.500
IWQOL Total 6.452 11.290 14.516 16.935 20.161 22.581 24.194 25.806 27.419 28.226
Table 10a. Percenti les Ass ociated wi th IWQOL-Lite Scor es for Obese Female Sample (BMI > 30) (n = 7,478)
Percentiles
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41
Physical Function .000 4.545 6.818 9.091 11.364 13.636 15.909 15.909 18.182 20.455 22.727 25.000 25.000 27.273 29.545 29.545 31.818 31.818 34.091 34.091 36.364 36.364 38.636 38.636 40.909 40.909 43.182 43.182 43.182 45.455 45.455 47.727 47.727 50.000 50.000 50.000 52.273 52.273 52.273 52.273 54.545
SelfEsteem .000 .000 .000 .000 3.571 3.571 3.571 7.143 7.143 10.714 10.714 10.714 14.286 14.286 14.286 17.857 17.857 17.857 21.429 21.429 21.429 25.000 25.000 25.000 25.000 28.571 28.571 28.571 28.571 32.143 32.143 32.143 32.143 35.714 35.714 35.714 35.714 35.714 39.286 39.286 39.286
Sexual Life .000 .000 .000 .000 .000 6.250 6.250 12.500 12.500 18.750 18.750 25.000 25.000 25.000 25.000 31.250 31.250 37.500 37.500 37.500 37.500 43.750 43.750 43.750 43.750 50.000 50.000 50.000 50.000 50.000 50.000 50.000 50.000 56.250 56.250 56.250 56.250 56.250 56.250 62.500 62.500
18
Public Distress .000 5.000 10.000 15.000 15.000 20.000 20.000 25.000 25.000 30.000 30.000 30.000 35.000 35.000 40.000 40.000 40.000 45.000 45.000 45.000 50.000 50.000 50.000 50.000 55.000 55.000 55.000 55.000 60.000 60.000 60.000 60.000 60.000 65.000 65.000 65.000 65.000 70.000 70.000 70.000 70.000
Work .000 6.250 12.500 18.750 25.000 25.000 31.250 31.250 31.250 37.500 37.500 43.750 43.750 43.750 43.750 50.000 50.000 50.000 50.000 50.000 56.250 56.250 56.250 56.250 56.250 62.500 62.500 62.500 62.500 62.500 62.500 68.750 68.750 68.750 68.750 68.750 68.750 68.750 75.000 75.000 75.000
IWQOL Total 6.452 11.290 14.516 16.935 20.161 22.581 24.194 25.806 27.419 28.226 29.839 31.452 33.065 33.871 35.484 36.290 37.903 38.710 39.516 41.129 41.935 42.742 43.548 44.355 45.161 46.774 46.823 48.387 49.194 50.000 50.000 51.613 52.419 53.226 54.032 54.839 54.839 55.645 56.452 57.258 58.065
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91
54.545 54.545 56.818 56.818 56.818 59.091 59.091 59.091 61.364 61.364 61.364 63.636 63.636 63.636 65.909 65.909 65.909 65.909 68.182 68.182 68.182 70.455 70.455 70.455 72.727 72.727 72.727 75.000 75.000 75.000 75.000 77.273 77.273 79.545 79.545 79.545 81.818 81.818 81.818 81.818 84.091 84.091 84.091 86.364 86.364 86.364 88.636 88.636 88.636 90.909
39.286 42.857 42.857 42.857 42.857 46.429 46.429 46.429 46.429 46.429 50.000 50.000 50.000 50.000 53.571 53.571 53.571 53.571 53.571 57.143 57.143 57.143 57.143 60.714 60.714 60.714 64.286 64.286 64.286 64.286 64.286 67.857 67.857 67.857 71.429 71.429 71.429 71.429 75.000 75.000 75.000 78.571 78.571 78.571 82.143 82.143 82.143 85.714 85.714 85.714
62.500 62.500 62.500 62.500 68.750 68.750 68.750 68.750 68.750 68.750 68.750 75.000 75.000 75.000 75.000 75.000 75.000 75.000 75.000 75.000 81.250 81.250 81.250 81.250 81.250 87.500 87.500 87.500 87.500 87.500 87.500 93.750 93.750 93.750 93.750 93.750 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
19
70.000 70.000 75.000 75.000 75.000 75.000 75.000 75.000 80.000 80.000 80.000 80.000 80.000 85.000 85.000 85.000 85.000 85.000 85.000 90.000 90.000 90.000 90.000 90.000 90.000 90.000 90.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
75.000 75.000 75.000 75.000 75.000 75.000 81.250 81.250 81.250 81.250 81.250 81.250 81.250 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
58.065 58.871 59.677 60.484 60.484 61.290 62.097 62.903 62.903 63.710 64.516 64.516 65.323 66.129 66.935 67.742 67.742 68.548 69.355 70.161 70.161 70.968 71.774 72.581 72.581 73.387 73.387 74.194 75.000 75.806 75.935 76.613 77.419 78.226 79.032 79.839 79.839 80.645 81.452 82.258 82.258 83.065 83.871 84.677 85.484 86.290 87.097 87.903 88.710 89.516
92 93 94 95 96 97 98 99
90.909 90.909 93.182 93.182 95.455 95.455 97.727 100.000
89.286 89.286 92.857 92.857 96.429 96.429 100.000 100.000
100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
20
100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
90.323 91.129 91.935 92.742 93.548 95.161 95.968 97.581
Table 10b. Percentiles Ass oci ated with IWQOL-Lite Scores fo r Obese Male Sample (BMI > 30) (n = 2,625)
Percentiles
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
Physical Function .000 4.545 6.818 9.091 13.636 15.909 18.182 20.455 25.000 25.000 27.273 29.545 31.818 34.091 34.091 36.364 38.636 40.182 40.909 43.182 43.182 45.455 47.727 47.727 47.727 50.000 50.000 52.273 52.273 54.545 54.545 54.545 56.818 56.818 56.818 59.091 59.091 59.091 61.364 61.364 63.636 63.636 63.636 63.636
SelfEsteem .000 3.571 7.143 14.143 15.000 17.857 21.429 21.429 25.000 25.000 28.571 32.143 32.143 35.714 35.714 39.286 39.286 42.857 42.857 42.857 46.429 46.429 46.429 50.000 50.000 50.000 53.571 53.571 53.571 53.571 57.143 57.143 57.143 60.714 60.714 60.714 60.714 60.714 64.286 64.286 64.286 64.286 64.286 67.857
Sexual Life .000 6.250 12.500 18.750 25.000 25.000 31.250 31.250 37.500 37.500 43.750 43.750 43.750 50.000 50.000 50.000 56.250 56.250 56.250 56.250 57.250 62.500 62.500 62.500 62.500 62.500 68.750 68.750 68.750 68.750 68.750 75.000 75.000 75.000 75.000 75.000 75.000 75.000 75.000 75.000 81.250 81.250 81.250 81.250
21
Public Distress 5.000 10.000 15.000 20.000 20.000 25.000 30.000 30.000 35.000 40.000 40.000 40.000 45.000 45.000 50.000 50.000 55.000 55.000 55.000 60.000 60.000 60.000 60.000 65.000 65.000 65.000 65.000 70.000 70.000 70.000 70.000 75.000 75.000 75.000 75.000 75.000 75.000 80.000 80.000 80.000 80.000 80.000 85.000 85.000
Work 6.250 12.500 25.000 31.250 37.500 37.500 43.750 43.750 50.000 50.000 50.000 50.000 56.250 56.250 56.250 56.250 62.500 62.500 62.500 62.500 62.500 62.500 68.750 68.750 68.750 68.750 68.750 68.750 75.000 75.000 75.000 75.000 75.000 75.000 75.000 75.000 75.000 81.250 81.250 81.250 81.250 81.250 81.250 81.250
IWQOL Total 10.484 17.742 21.774 25.000 28.226 30.645 33.871 35.484 37.097 38.710 40.323 42.742 43.855 45.968 46.774 48.387 50.000 51.613 52.419 53.226 54.839 55.645 56.452 57.258 58.871 59.677 59.677 60.484 61.726 62.097 62.903 63.710 64.516 65.323 66.129 66.935 67.742 68.548 68.548 69.355 70.161 70.161 70.968 71.774
45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
65.909 65.909 65.909 68.182 68.182 70.455 70.455 70.455 72.727 72.727 72.727 75.000 75.000 75.000 75.000 75.000 77.273 77.273 77.273 78.727 79.545 79.545 79.545 81.818 81.818 81.818 81.818 84.091 84.091 84.091 84.091 86.364 86.364 86.364 86.364 86.364 88.636 88.636 88.636 88.636 90.909 90.909 90.909 90.909 93.182 93.182 93.182 95.455 95.455 95.455
67.857 67.857 67.857 67.857 71.429 71.429 71.429 71.429 71.429 75.000 75.000 75.000 75.000 75.000 75.000 78.571 78.571 78.571 78.571 78.571 82.143 82.143 82.143 82.143 85.714 85.714 85.714 85.714 85.714 85.714 89.286 89.286 89.286 89.286 92.714 92.857 92.857 92.857 92.857 92.857 96.429 96.429 96.429 96.429 96.429 100.000 100.000 100.000 100.000 100.000
81.250 81.250 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
22
85.000 85.000 85.000 85.000 90.000 90.000 90.000 90.000 90.000 90.000 90.000 90.000 90.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 95.000 96.250 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
81.250 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 87.500 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 93.750 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000 100.000
72.581 73.387 74.194 74.194 75.000 75.000 75.806 76.613 77.242 77.419 78.226 78.226 79.032 79.839 80.645 80.645 81.452 81.452 82.258 83.065 83.065 83.871 83.871 84.677 85.484 85.484 86.290 86.290 87.097 87.097 87.097 87.903 88.710 88.710 89.516 89.516 90.323 91.129 91.129 91.935 91.935 92.742 92.742 93.548 94.355 94.355 95.161 95.161 95.968 95.968
95 96 97 98 99
95.455 97.727 97.727 100.000 100.000
100.000 100.000 100.000 100.000 100.000
100.000 100.000 100.000 100.000 100.000
23
100.000 100.000 100.000 100.000 100.000
100.000 100.000 100.000 100.000 100.000
96.774 97.581 98.387 98.387 100.000
Table 11: Conversio n of Raw Scores to Trans form ed (0-100) Scor es Raw Physical SelfSexual Public Work Score Function Esteem Life Distress 4 100 100 5 93.8 100 93.8 6 87.5 95.0 87.5 7 100 81.3 90.0 81.3 8 96.4 75.0 85.0 75.0 9 92.9 68.8 80.0 68.8 10 89.3 62.5 75.0 62.5 11 100 85.7 56.3 70.0 56.3 12 97.7 82.1 50.0 65.0 50.0 13 95.5 78.6 43.8 60.0 43.8 14 93.2 75.0 37.5 55.0 37.5 15 90.9 71.4 31.3 50.0 31.3 16 88.6 67.9 25.0 45.0 25.0 17 86.4 64.3 18.8 40.0 18.8 18 84.1 60.7 12.5 35.0 12.5 19 81.8 57.1 6.3 30.0 6.3 20 79.5 53.6 0 25.0 0 21 77.3 50.0 20.0 22 75.0 46.4 15.0 23 72.7 42.9 10.0 24 70.5 39.3 5.0 25 68.2 35.7 0 26 65.9 32.1 27 63.6 28.6 28 61.4 25.0 29 59.1 21.4 30 56.8 17.9 31 54.5 14.3 32 52.3 10.7 33 50.0 7.1 34 47.7 3.6 35 45.5 0 36 43.2 37 40.9 38 38.6 39 36.4 40 34.1 41 31.8 42 29.5 43 27.3 44 25.0 45 22.7 46 20.5 47 18.2 48 15.9 49 13.6
24
Total Score
100 99.2 98.4 97.6 96.8 96.0 95.2 94.4 93.5 92.7 91.9 91.1 90.3 89.5 88.7 87.9 87.1 86.3 85.5
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
11.4 9.1 6.8 4.5 2.3 0
84.7 83.9 83.1 82.3 81.5 80.6 79.8 79.0 78.2 77.4 76.6 75.8 75.0 74.2 73.4 72.6 71.8 71.0 70.2 69.4 68.5 67.7 66.9 66.1 65.3 64.5 63.7 62.9 62.1 61.3 60.5 59.7 58.9 58.1 57.3 56.5 55.6 54.8 54.0 53.2 52.4 51.6 50.8 50.0 49.2 48.4 47.6 46.8 46.0
25
99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147
45.2 44.4 43.5 42.7 41.9 41.1 40.3 39.5 38.7 37.9 37.1 36.3 35.5 34.7 33.9 33.1 32.3 31.5 30.6 29.8 29.0 28.2 27.4 26.6 25.8 25.0 24.2 23.4 22.6 21.8 21.0 20.2 19.4 18.5 17.7 16.9 16.1 15.3 14.5 13.7 12.9 12.1 11.3 10.5 9.7 8.9 8.1 7.3 6.5
26
148 149 150 151 152 153 154 155
5.6 4.8 4.0 3.2 2.4 1.6 0.8 0
27
Table 12: IWQOL-Lite Six-Month Change Scores for Men Weight Loss Group
Weight Gain
0-4.9% Loss
5-9.9% Loss
1014.9% Loss
Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range
Physical Function Change 2.188 134 12.018 2.266
SelfEsteem Change 3.966 134 16.342 3.560
-45.5 34.1 79.6 6.192 467 13.257 4.545
-57.2 64.3 121.5 6.783 466 13.424 3.596
-50.0 61.4 111.4 9.969 374 13.984 9.084
-53.5 67.9 121.4 10.548 372 15.025 7.161
-52.3 77.3 129.5 16.719 170 16.107 13.645
-32.2 92.9 125.1 12.259 169 15.865 10.706
-52.3 79.5 131.8
-39.3 67.9 107.2
28
Sexual Life Change 1.046 132 17.800 1.364E02 -100.0 50.0 150.0 3.293 464 16.067 2.279E02 -100.0 75.0 175.0 4.106 369 15.246 2.528E02 -75.0 87.5 162.5 7.329 169 17.171 3.519E02 -56.2 81.3 137.5
Public Distress Change 1.045 134 10.744 .467
-30.0 35.0 65.0 2.591 467 10.969 2.189 -50.0 50.0 100.0 4.251 374 11.698 2.464 -50.0 50.0 100.0 5.794 170 11.946 3.039 -20.0 65.0 85.0
Work Change
-.894 132 16.830 2.128E03 -62.5 50.0 112.5 2.967 461 13.673 2.389E02 -56.3 56.3 112.5 3.704 372 11.744 3.242E02 -37.5 43.8 81.3 5.828 170 15.604 4.697E02 -62.5 56.3 118.8
IWQOLLite Total Change 1.930 134 9.562 2.377
-25.8 29.0 54.8 4.926 467 9.622 4.039 -43.6 49.2 92.8 7.602 374 10.063 6.474 -35.5 54.8 90.3 11.308 170 11.679 9.487 -35.5 58.9 94.3
15% + Loss
All Men
Mean N Std. Deviation Grouped Median
19.745 88 16.139 18.170
16.089 87 18.335 13.067
9.126 87 14.065 5.523
9.148 88 16.050 5.000
Minimum Maximum Range Mean N Std. Deviation Grouped Median
-11.4 61.4 72.8 9.321 1233 14.830 6.858
-35.8 60.7 96.5 9.029 1228 15.294 7.143
-35.0 60.0 95.0 3.836 1233 11.883 2.917
-52.3 79.5 131.8
-57.2 92.9 150.1
-18.8 62.5 81.3 4.270 1221 16.159 2.642E02 -100.0 87.5 187.5
Minimum Maximum Range
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-50.0 65.0 115.0
5.132 87 13.344 3.611E02 -25.0 50.0 75.0 3.326 1222 13.860 2.843E02 -62.5 56.3 118.8
13.905 88 11.805 11.669 -12.1 49.2 61.3 6.933 1233 10.705 5.657 -43.6 58.9 102.4
Weight Gain
0-4.9% Loss
5-9.9% Loss
10-14.9% Loss
15% + Loss
All Women
Table 13: IWQOL-Lite Six-Month Change Scores for Women 2.576 8.208 4.861 2.113 1.955 Mean 389 388 376 388 387 N 13.975 17.654 19.114 13.388 15.524 Std. Deviation 2.273 7.120 2.885E-02 2.026 1.849E-02 Grouped Median -59.3 -46.4 -81.2 -70.0 -56.3 Minimum 56.9 64.3 81.3 50.0 62.5 Maximum 116.2 110.7 162.5 120.0 118.8 Range 8.501 11.778 5.829 4.004 4.572 Mean 1092 1086 1045 1089 1087 N 14.177 17.426 21.138 13.227 15.349 Std. Deviation 6.827 10.714 4.411E-02 3.420 3.447E-02 Grouped Median -52.3 -75.0 -100.0 -75.0 -75.0 Minimum 68.2 92.9 100.0 55.0 75.0 Maximum 120.5 167.9 200.0 130.0 150.0 Range 12.261 14.405 8.669 5.343 5.510 Mean 912 910 864 912 905 N 14.107 18.234 20.197 14.001 14.775 Std. Deviation 9.988 14.257 2.165 1.799 4.108E-02 Grouped Median -54.5 -57.1 -75.0 -50.0 -50.0 Minimum 75.0 85.7 100.0 90.0 87.5 Maximum 129.6 142.8 175.0 140.0 137.5 Range 16.435 19.167 11.540 6.897 7.715 Mean 535 532 505 535 531 N 15.217 19.664 19.667 13.578 15.648 Std. Deviation 6.263 5.000 2.238 Grouped Median 15.870 17.857 -50.0 -57.1 -56.3 -60.0 -62.5 Minimum 68.2 100.0 100.0 90.0 62.5 Maximum 118.2 157.1 156.3 150.0 125.0 Range 18.997 21.162 13.972 8.814 8.391 Mean 350 349 331 350 348 N 16.209 21.358 21.400 15.153 15.637 Std. Deviation 6.291 4.167 .809 Grouped Median 15.918 21.407 -25.0 -50.0 -37.5 -30.0 -37.5 Minimum 70.4 89.3 100.0 80.0 75.0 Maximum 95.4 139.3 137.5 110.0 112.5 Range 11.260 14.293 8.286 5.140 5.442 Mean 3278 3265 3121 3274 3258 N 15.284 18.906 20.635 13.854 15.397 Std. Deviation 9.091 12.292 4.395 1.928 3.985E-02 Grouped Median -59.3 -75.0 -100.0 -75.0 -75.0 Minimum 75.0 100.0 100.0 90.0 87.5 Maximum 134.4 175.0 200.0 165.0 162.5 Range
30
3.956 389 11.434 3.226 -39.8 46.0 85.9 7.674 1092 11.359 6.452 -69.4 54.8 124.2 10.266 912 11.635 9.095 -50.0 62.1 112.1 13.766 534 12.453 12.619 -53.2 75.8 129.1 15.837 350 13.531 13.716 -29.8 63.7 93.6 9.819 3277 12.366 8.871 -69.4 75.8 145.2
Weight Gain
0-4.9% Loss
5-9.9% Loss
10-14.9% Loss
15% + Loss
All subjects
Table 14: IWQOL-Lite Six-Month Change Scores for Total Sample 2.477 7.119 3.869 1.839 1.231 Mean 523 522 508 522 519 N 13.491 17.411 18.838 12.760 15.898 Std. Deviation 2.273 3.582 2.432E-02 1.643 1.451E-02 Grouped Median -59.3 -57.2 -100.0 -70.0 -62.5 Minimum 56.9 64.3 81.3 50.0 62.5 Maximum 116.2 121.5 181.3 120.0 125.0 Range 7.810 10.278 5.049 3.580 4.094 Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range Mean N Std. Deviation Grouped Median Minimum Maximum Range
1559 13.944 6.818 -52.3 68.2 120.5 11.595 1286 14.105 9.105 -54.5 77.3 131.8 16.504 705 15.425 13.682 -52.3 79.5 131.8 19.147 438 16.179 15.941 -25.0 70.4 95.4 10.730 4511 15.185 9.091 -59.3 79.5 138.8
1552 16.483 7.163 -75.0 92.9 167.9 13.286 1282 17.446 10.714 -57.1 92.9 150.0 17.502 701 19.039 15.490 -57.1 100.0 157.1 20.150 436 20.869 17.857 -50.0 89.3 139.3 12.854 4493 18.142 10.714 -75.0 100.0 175.0
31
1509 19.747 3.571E-02 -100.0 100.0 200.0 7.303 1233 18.962 4.555E-02 -75.0 100.0 175.0 10.484 674 19.146 3.059 -56.3 100.0 156.3 12.964 418 20.176 6.278 -37.5 100.0 137.5 7.157 4342 19.562 4.451E-02 -100.0 100.0 200.0
1556 12.605 2.977 -75.0 55.0 130.0 5.025 1286 13.377 1.757 -50.0 90.0 140.0 6.631 705 13.203 4.982 -60.0 90.0 150.0 8.881 438 15.319 4.321 -35.0 80.0 115.0 4.783 4507 13.355 1.789 -75.0 90.0 165.0
1548 14.883 3.088E-02 -75.0 75.0 150.0 4.984 1277 13.980 3.826E-02 -50.0 87.5 137.5 7.257 701 15.647 1.443 -62.5 62.5 125.0 7.740 435 15.248 4.887E-02 -37.5 75.0 112.5 4.865 4480 15.021 3.644E-02 -75.0 87.5 162.5
3.437 523 11.011 2.455 -39.8 46.0 85.9 6.851 1559 10.937 5.645 -69.4 54.8 124.2 9.492 1286 11.262 8.099 -50.0 62.1 112.1 13.172 704 12.308 11.692 -53.2 75.8 129.1 15.449 438 13.212 13.710 -29.8 63.7 93.6 9.030 4510 12.003 8.043 -69.4 75.8 145.2
Six-Month Changes in IWQOL-Lite Scores for Weight Loss Participants (n = 4511) Figures 1-6
32
33
34
35
36
37
IWQOL-Lite Scoring Raw scores for each scale are computed for each of the five scales only if a minimum of 50% of the items for that scale are answered, and for the total score only if 75% o f the answers for all items are completed. (The required number o f minimum responses is: Physical Function=6 of 11; Self-Esteem =4 of 7; Sexual Life=2 of 4; Public Distress=3 of 5; Work=2 of 4; Total=24 of 31.) In computing raw scores, we use a pro-rated system for handling missing data. To calculate the raw score for any scale or total score, the procedures are as follows: 1- Determine if the minimum number of items are answered for that scale. The required number of minimum responses is: Physical Function=6 o f 11; Self-Esteem =4 of 7; Sexual Life=2 of 4; Public Distress=3 of 5; Work=2 of 4; Total=24 of 31. Example 1: If an individual answered 5 of 11 Physical Function questions, the Physical Function score would be considered missing and coded as 999. Example 2: If an individual answered 26 items on the entire scale, a valid score would be calculated for the IWQOL-Lite total. 2- Take the average of the valid items for that scale. Compute t he average for the valid responses to items for that scale where 1=”Never True” and 5=”Always True”. The average must be a number between 1 and 5. For example, if the respondent answered “3” on every item of the Physical Function scale, the mean would be 3. Example 3: An individual answered the 11 Physical Function questions as follows (9 indicates missing question): 2, 3, 2, 4, 9, 2, 2, 3, 4, 9, 5. The individual answered 9 of 11 questions, with an average of 3.0 (27/9). Example 4: An individual answered the 5 Public Distress questions as follows: 3, 1, 3, 4, 3. The individual answered 5 of 5 questions with an average of 2.8 (14/5). 3- Multiply that average by the tot al number of items for that scale. The total nu mber of items on IWQOL-Lite scales are as follows: Physical Function=11, Se lf-Esteem=7, Sexual Life=4, Public Distress=5, Work=4, Total=31). Round to t he nearest whole integer. For example, if the mean o f the Physical Function scale is 3.0, t hen you would multiply 3.0 X 11 = 33. Example 5: From the Physical Function answers in Example 3, multiply the average (3.0) times the number of total questions in the Physical Fu nction scale (11) and round to the nearest whole integer: 3 X 11 = 33 (no need to round). This is the Physical Function Raw Score. Example 6: From the Public Distress answers in Example 4, multiply the average (2.8) times the number of total questions in the Public D istress scale (5) and round to the
38
nearest whole integer: 2.8 X 5 = 14 (no need to round). This is the Public Distress Raw Score. Round to the nearest whole integer. For example, here is the code for calculating total score:
***** Compute TOTAL Score. count misstot = IWPF1 TO IWWRK4 (9,missing,sysmis). do if (misstot lt 8). compute IWTOT = rnd((sum(IWPF1 TO IWWRK4 )/(31-misstot))*31). end if. if (misstot ge 8) IWTOT = 999. var lab IWTOT 'Impact Total Score (Brief)'. mis val IWTOT (999).
Here is the code for calculating the individual scales of the IWQOL-Lite:
***** Compute PHYSICAL FUNCTION Score. count misspf = IWPF1 TO IWPF11 (9,missing,sysmis). do if (misspf lt 6). compute IWPF = rnd((sum(IWPF1 TO IWPF11 )/(11-misstpf))*11). end if. if (misspf ge 6) IWPF = 999. var lab IWPF 'Impact Physical Function (Brief)'. mis val IWPF (999).
***** Compute SELF-ESTEEM Score.
39
count missse = IWSE1 TO IWSE7 (9,missing,sysmis). do if (missse lt 4). compute IWSE = rnd((sum(IWSE1 TO IWSE7 )/(7-misstse))*7). end if. if (missse ge 4) IWSE = 999. var lab IWSE 'Impact Self-Esteem (Brief)'. mis val IWSE (999).
***** Compute SEXUAL LIFE Score. count misssl = IWSL1 TO IWSL4 (9,missing,sysmis). do if (misssl lt 3). compute IWSL = rnd((sum(IWSL1 TO IWSL4 )/(4-misstsl))*4). end if. if (misssl ge 3) IWSL = 999. var lab IWPF 'Impact Sexual Life (Brief)'. mis val IWSL (999).
***** Compute PUBLIC DISTRESS Score. count misspd = IWPD1 TO IWPD5 (9,missing,sysmis). do if (misspd lt 3). compute IWPD = rnd((sum(IWPD1 TO IWPD5 )/(5-misstpd))*5). end if. if (misspd ge 3) IWPD = 999. var lab IWPD 'Impact Public Distress (Brief)'. mis val IWPD (999).
40
***** Compute WORK Score. count misswk = IWWK1 TO IWWK4 (9,missing,sysmis). do if (misswk lt 3). compute IWWK = rnd((sum(IWPF1 TO IWPF4 )/(11-misstwk))*4). end if. if (misswk ge 3) IWWK = 999. var lab IWW K 'Impact Work (Brief)'. mis val IWWK (999).
We have been converting the IWQOL-Lite raw scores to the more familiar 0 (worst) to 100 (best) scoring using the following formulae: 1. Subtract the raw score (as calculated above) from the maximum score for each scale (Physical Function=55, Self-Esteem=35, Sexual Life=20, Public D istress=25, Work=20, Total=155). 2. Divide that difference by the range for each scale (Physical Function=44, SelfEsteem=28, Sexual Life=16, Public Distress=20, Work=16, Total=124). 3. Multiply that total by 100. Example 7: From the Physical Funct ion answers in Example 5, subtract the raw score (33) from the maximum score for Physical Funct ion (55) and divide that result by the range for Physical Function (44) and multiply the result by 100: (55 - 33)/44 = .50 X 100 = 50. Example 8: From the Public Distress answers in Example 6, subtract the raw score (14) from the maximum score for Public Distress (25) and divide that result by the range for Public Distress (20) and multiply by 100: (25 - 14)/20 = .55 X 100 = 55. An easy way to check the scoring is to enter a record with all 1's and a second record with all 5's. The first record should have a ll transformed scores equal to 100 and the second record should have all transformed scores equa l to 0. For example: Physical Function: ((55-33)/44)) = 50 compute iwpft = ((55-iwpf)/44)*100.
41
compute iwset = ((35-iwse)/28)*100. compute iwsext = ((20-iwsex)/16)*100. compute iwpdt = ((25-iwpd)/20)*100. compute iwwrkt = ((20-iwwrk)/16)*100. compute iwtott = ((155-iwtot)/124)*100.
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How to Convert IWQOL Long form item responses to IWQOL-Lite Scoring * THI S PROGRAM CONVERTS I WQOL FI LES FROM OLD VERSI ON TO LI TE VERSI ON AND SCORES LI TE VERSI ON. RENAME VAR ( mob8, mob6, mob4, mob7, mob2, mob1, mob5, hl t h4, hl t h10, hl t h8, hl t h1, se4, se2, se1, se8, si 11, se7, si 2, sex6, sex2, sex4, sex5, s i 5, adl 7, adl 3, adl 2, s i 3, wr k1, wr k3, wr k4, wr k5 = I WPF1 TO I WPF11 I WSE1 TO I WSE7 I WSEX1 TO I WSEX4 I WPD1 TO I WPD5 I WWRK1 TO I WWRK4) . SAVE OUTFI LE=' C: \ DATA\ Kol ot ki n\ Nor ms\ t emp. sav' / COMPRESSED/ KEEP = I D SI TE I WPF1 I WPF2 I WPF3 I WPF4 I WPF5 I WPF6 I WPF7 I WPF8 I WPF9 I WPF10 I WPF11 I WSE1 I WSE2 I WSE3 I WSE4 I WSE5 I WSE6 I WSE7 I WSEX1 I WSEX2 I WSEX3 I WSEX4 I WPD1 I WPD2 I WPD3 I WPD4 I WPD5 I WWRK1 I WWRK2 I WWRK3 I WWRK4. VAR LAB I WPF1 ' Troubl e pi cki ng up obj ect s' / I WPF2 ' Troubl e t yi ng shoes' / I WPF3 ' Di f f i c ul t y get t i ng up f r o m c hai r s ' / I WPF4 ' Tr oubl e usi ng st ai r s' / I WPF5 ' Di f f i c ul t y dr e ss i ng' / I WPF6 ' Tr oubl e wi t h mobi l i t y' / I WPF7 ' Tr oubl e cr ossi ng l egs' / I WPF8 ' Feel shor t of br eat h' / I WPF9 ' Pai nf ul s t i f f j oi nt s ' / I WPF10 ' Ankl es & l egs swol l en' / I WPF11 ' Worr i ed about heal t h' / I WSE1 ' Sel f - consci ous' / I WSE2 ' Sel f - est eem not what i t coul d be' / I WSE3 ' Feel unsur e of sel f ' / I WSE4 ' Do not l i ke mysel f ' / I WSE5 ' Af r ai d of bei ng r ej ect ed' / I WSE6 ' Avoi d l ooki ng i n mi r r or s' / I WSE7 ' Embar assed i n publ i c pl aces' / I WSEX1 ' Do not enj oy sexual act i vi t y' / I WSEX2 ' Have l i t t l e sexual desi r e' / I WSEX3 ' Di f f i cul t y wi t h sexual per f or mance' / I WSEX4 ' Avoi d sexual encount er s' / I WPD1 ' Exper i ence r i di cul e & t easi ng' / I WPD2 ' Wor r y about f i t t i ng i n publ i c seat s' / I WPD3 ' Wor r y about f i t t i ng t hr ough ai sl es' / I WPD4 ' Wor r y about f i ndi ng chai r s' / I WPD5 ' Exper i ence di scr i mi nat i on' / I WWRK1 ' Tr oubl e get t i ng t hi ngs accompl i shed' / I WWRK2 ' Less pr oduct i ve t han I coul d be' / I WWRK3 ' Do not r ecei ve appr opr i at e recogni t i on' / I WWRK4 ' Af r ai d t o go on j ob i nt er vi ews' . VAL LAB I WPF1 TO I WWRK4 5 ' Al ways Tr ue' 4 ' Usual l y Tr ue' 3 ' Somet i mes Tr ue' 2 ' Rar el y Tr ue' 1 ' Never Tr ue' . FORMAT I WPF1 TO I WWRK4 ( F1. 0) . MI S VAL I WPF1 TO I WWRK4 ( 9) .
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EXEC. ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** NEW SCORI NG FOR BRI EF I WQOL**** *** *** *** *** *** *** **. **** * Comput e PHYSI CAL Scor e. count mi ss phys = I WPF1 TO I WPF11 ( 9, mi ss i ng, sysmi s) . do i f ( mi ssphys l t 6) . comput e I WPF = r nd( ( sum( I WPF1 TO I WPF11 ) / ( 11- mi ss phys) ) *11) . end i f . i f ( mi ss phys ge 6) I WPF = 999. var l ab I WPF ' Physi cal Funct i on Scor e ( Br i ef ) ' . mi s val I WPF ( 999) . r ecode I WPF ( sysmi s=999) . f r eq mi ssphys I WPF. ** ** * Comput e SELF- ESTEEM Scor e. count mi ss si = I WSE1 TO I WSE7 ( 9, mi ss i ng, sysmi s) . do i f ( mi s ss i l t 4) . comput e I WSE = r nd( ( sum( I WSE1 TO I WSE7 ) / ( 7- mi ss si ) ) *7) . end i f . i f ( mi sssi ge 4) I WSE = 999. var l ab I WSE ' I mpact Sel f - Est eem ( Br i ef ) ' . mi s val I WSE ( 999) . r ecode I WSE ( sys mi s=999) . f r eq mi sssi I WSE. **** * Comput e SEXUAL LI FE Scor e. count mi ss sex = I WSEX1 TO I WSEX4 ( 9, mi ss i ng, sys mi s) . do i f ( mi s ss ex l t 3) . comput e I WSEX = r nd( ( sum( I WSEX1 TO I WSEX4 ) / ( 4- mi ss sex) ) *4) . end i f . i f ( mi ss sex ge 3) I WSEX = 999. var l ab I WSEX ' I mpact Sexual Li f e Scor e ( Br i ef ) ' . mi s val I WSEX ( 999) . r ecode I WSEX ( sys mi s=999) . f r eq mi ss sex I WSEX. **** * Comput e PUBLI C DI STRESS Scor e. count mi ss pub = I WPD1 TO I WPD5 ( 9, mi ss i ng, sys mi s) . do i f ( mi sspub l t 3) . comput e I WPD = r nd( ( sum( I WPD1 TO I WPD5) / ( 5- mi ss pub) ) *5) . end i f . i f ( mi ss pub ge 3) I WPD = 999. var l ab I WPD ' I mpact Publ i c Di st r ess Scor e ( Br i ef ) ' . mi s val I WPD ( 999) . r ecode I WPD ( sys mi s=999) . f r eq mi ss pub I WPD. **** * Comput e WORK Scor e. count mi sswr k = I WWRK1 TO I WWRK4 ( 9, mi ss i ng, sysmi s) . do i f ( mi s swr k l t 3) . comput e I WWRK = r nd( ( sum( I WWRK1 TO I WWRK4 ) / ( 4- mi sswr k) ) *4) . end i f . i f ( mi ss wr k ge 3) I WWRK = 999. var l ab I WWRK ' I mpact Work Scor e ( Br i ef ) ' . mi s val I WWRK ( 999) . r ecode I WWRK ( sys mi s=999) . f r eq mi ss wr k I WWRK. **** * Comput e TOTAL Scor e. count mi ss t ot = I WPF1 TO I WWRK4 ( 9, mi ss i ng, sysmi s) . do i f ( mi s st ot l t 8) . comput e I WTOT = r nd( ( sum( I WPF1 TO I WWRK4 ) / ( 31- mi ss t ot ) ) *31) .
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end i f . i f ( mi sst ot ge 8) I WTOT = 999. var l ab I WTOT ' I mpact Tot al Scor e (Br i ef ) ' . mi s val I WTOT ( 999) . r ecode I WTOT ( sys mi s=999) . f r eq mi sst ot I WTOT. FORMAT i wpf i wse i wsex i wpd i wwr k i wt ot ( F3. 0) . ** ** ** ** * ** ** * ** CONVERT SCORES TO T- SCORE FORMAT * ** ** ** ** ** * ** ** * ** . comput e i wpf t = ( ( 55- i wpf ) / 44) *100. comput e i wset = ( ( 35- i wse) / 28) *100. comput e i wsext = ( ( 20- i wsex) / 16) *100. comput e i wpdt = ( ( 25- i wpd) / 20) *100. comput e i wwr kt = ( ( 20- i wwr k) / 16) *100. comput e i wt ot t = ( ( 155- i wt ot ) / 124) *100. exec. var l ab i wpf t ' I WQOL Physi cal Funct i on T- Scor e' / i wset ' I WQOL Sel f - Est eem T- Scor e' / i wsext ' I WQOL Sexual Li f e T- Scor e' / i wpdt ' I WQOL Publ i c Di st r ess T- Scor e' / i wwr kt ' I WQOL Wor k T- Scor e' / i wt ot t ' I WQOL Tot al T- Scor e' . f or mat i wpf t t o i wt ot t ( f 5. 1) . r ecode i wpf t t o i wt ott ( sysmi s=999) . mi s val i wpf t t o i wt ot t ( 999) .
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References 1 WHO. Constitution of the World Health Organization. July 22, 1946; WHO: Geneva. 2 Ware JE. Standards for validating health measures: definition and content. J Chron Dis 1987;40: 473-80. 3 Testa MA, Simonson DC. Assessment of quality of life outcomes. N. Engl. J. Med. 1996;334:833-40. 4 Fontaine KR, Bartlett SJ. Estimating health-related quality of life in obese individuals. Dis Manage Health Outcomes 1998;3:61-70. 5 World Health Organization. World Health Report-Life in the 21st century: A vision for all, WHO: Geneva. 1998. 6 Fontaine KR, Barofsky I. Obesity and health-related quality of life. Obesity Reviews 2001;2:173-82. 7 Kolotkin RL, Meter K, Williams GR. Quality of life and obesity. Obesity Reviews 2001;2:219-29. 8 Kushner RF, Foster G. Obesity and quality of life. Nutrition 2000;16:947-52. 9 Sullivan M, Karlsson J, Sjostrom L, Taft C. Why quality of life measures should be used in the treatment of patients with obesity. 2001. In: International Textbook of Obesity. Bjorntorp P, ed.; John Wiley & Sons: New York: 485-510. 10 Brown WJ, Dobson AJ, Mishra G. What is a healthy weight for middle aged women? Int. J. Obes. 1998;22:520-8. 11 Doll HA, Petersen SEK, Stewart-Brown SL. Obesity and physical and emotional well-being: Associations between body mass index, chron ic illness, and the physical and mental components of the SF-36 questionnaire. Obes. Res. 2000;8:160-70. 12 Fine JT, Colditz GA, Coakley EH, et al. A prospective study of weight change and health-related quality of life in women. JAMA 1999;282:2136-42. 13 Kolotkin RL, Crosby RD, Kosloski KD, Williams GR. Development of a brief measure to assess quality of life in obesity. Obes. Res. 2001;9:102-11. 14 Fontaine KR, Cheskin LJ, Barofsky I. Health-related quality of life in obese persons seeking treatment. J. Fam. Pract. 1996;43:265-70. 15 LePen C, Levy E, Loos F, Banzet M, Basdevant A. 'Specific' scale compared with 'generic' scale: a double measurement of the quality of life in a Frenc h community sample of obese subjects. J Epidemiol Commun Hlth 1998;52:445-50. 16 Rippe JM, Price JM, Hess SA, et al. Improved psychological well being, quality of life, and health practices in moderately o verweight women participating in a 12-week structured weight loss program. Obes. Res. 1998;6:208-18. 17 Kolotkin RL, Crosby RD, Williams GR, Hartley GG, Nicol S. The relationship between health-related quality of life and weight loss. Obes. Res. 2001;9:564-71. 18 Samsa GP, Kolotkin RL, Williams GR, Nguyen MR, Mendel C. Effect of moderate weight loss on health-related quality of life: an analysis o f combined data from 4 randomized trials of sibutramine vs. placebo. Am J Managed Care 2001;7:875-83. 19 Wadden TA, Phelan S. Assessment of quality of life in obese individuals. Obes. Res. 2002;10 Suppl 1:50S-7S. 20 Kolotkin RL, Head S, Hamilton MA, Tse CTJ. Assessing impact of weight on quality of life. Obes. Res. 1995;3:49-56.
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21 Crosby RD, Kolotkin RL, Williams GR. An integrated method to determine meaningful changes in health-related quality of life. J. Clin. Epidemiol. 2004;57:1153-60. 22 Crosby RD, Kolotkin RL, Williams GR. Defining clinically meaningful change in health-related quality of life. J. Clin. Epidemiol. 2003;56:395-407.
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©
Publications for IWQOL-Lite (and its predecessor IWQOL) Bibliographic references of the original questionnaire
Kolotkin RL, Head S, Hamilton MA, Tse CTJ. Assessing impact of weight on quality of life. Obesity Research. 1995;3:49-56. Kolotkin RL, Head S, Brookhart A. Construct validity of the Impact of Weight o n Quality of Life questionnaire. Obesity Research. 1997;5:434-441. Kolotkin RL, Crosby RD, Kosloski KD, Williams GR. Development o f a brief measure to assess quality of life in obesity. Obesity Research. 2001;9:102-111. Kolotkin RL, Crosby RD. Psychometric evaluation of the Impact Of Weight On Quality Of Life-Lite Questionnaire (IWQOL-Lite) in a co mmunity sample. Quality of Life Research. 2002;11:157-171. Other IWQOL and IWQOL-Lite publications
Di Francesco V, Sacco T, Zamboni M, et al. Weight Loss and Quality of Life Improvement in Obese Subjects Treated with Sibutramine: A Double-Blind Randomized Multicenter Study. Annals of Nutrition and Metabolism. 2007; 51:75-81. Stucki A, Borchers M, Stucki G, Cieza A, Amann E, Ruof J. Content comparison of health status measures for obesity based on t he international classification of functioning, disability and health. International Journal of Obesity (London) 2006; 30: 1791-1799. Duval K, Marceau P, Perusse L, Lacasse Y. An overview of obesity-specific quality o f life questionnaires. Obesity Reviews 2006; 7: 347-360. Tuthill A, Slawik H, O'Rahilly S, Finer N. Psychiatric co-morbidities in patients attending specialist obesity services in the UK. QJM - Mo nthly Journal of the Association of Physicians 2006; 99: 317-325. Kolotkin R, Crosby R, Corey-Lisle P, Li H, Swanson J. Performance of a weight-related measure of quality of life in a psychiatric sample. Qua lity of Life Research 2006; 15: 587-596. Kolotkin R L, Binks M, Crosby R D, Ostbye T, Gress R E, Adams T D. Obesity and sexual quality of life. Obesity (Silver Spring) 2006; 14: 472- 479. Rieger E, Wilfley DE, Stein RI, Marino V, Crow SJ. A comparison of quality of life in obese individuals with and without binge eat ing disorder. International Journal of Eating Disorders. 2005;37:234-240.
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Engel, S.G., Kolotkin, R.L, Teixeira P,J., Sardinha L.B., Vieira P.N., Palmeira A.L., Crosby R.D. Psychometric and Cross-National Evaluation of a Po rtuguese Version of the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) Questionnaire. European Eating Disorders Review. 2005;13:133-143. Adami G.F., Ramberti G., Weiss A., Carlini F., Murelli F., Scopinaro N. Quality of life in obese subjects following biliopancreatic diversion. Behavioral Medicine. 2005;31:53-60. Teixeira PJ, Going SB, Houtkooper LB, Cussler EC, Metcalfe LL, Blew RM, Sard inha LB, Lohman TG: Pretreatment predictors of attrition and successful weight management in women. International Journal of Obesity. 2004;28:1124-33. Teixeira PJ, Palmeira AL, Branco TL, Martins SS, Minderico CS, Barata JT, Silva AM, Sardinha LB: Who will lose weight? A reexamination o f predictors of weight loss in women. International Journal of Behavioral Nutrition and Physical Act ivity. 2004;1:12. Kolotkin, R.L., Westman, E.C., Østbye, T., Crosby, R.D., Binks, M., Eisenson, H.E. Weight-related Quality of Life in Obese Persons With and Without Binge Eat ing Disorder. Obesity Research. 2004;12:999-1005. White, M.A., O'Neil, P. M, Kolotkin, R.L, Byrne, T.K. Gender, Race, and ObesityRelated Quality of Life at Extreme Levels of Obesity. Obesity Research. 2004;12:949955. Crosby RD, Kolotkin RL, Williams GR. An integrated method to determine meaningful changes in health-related quality of life. Journal o f Clinical Epidemiology. 2004;57:115360. Boan J, Kolotkin RL, Westman EC, McMahon RL , Grant JP. Binge Eating, Quality of Life and Physical Activity Improve After Roux-en-Y Gastric Bypass (RYGB) for Morbid Obesity. Obesity Surgery. 2004;14:341-348. Brazier JE, Kolotkin RL, Crosby RD, Williams GR. Estimating a Preference-Based Single Index for the Impact of Weight on Quality of Life-Lite Instrument (IWQOL-Lite) from the SF-6D. Value in Health. 2004;7:490-498. Korolija, D.; Sauerland, S.; Wood-Dauphinee, S.; Abbou, C. C.; Eypasch, E.; Caballero, M. G.; Lumsden, M. A.; Millat, B.; Monson, J. R.; Nilsson, G.; Pointner, R.; Schwenk, W.; Shamiyeh, A.; Szold, A.; Targarona, E.; Ure, B.; Neugebauer, E. Evaluation of quality of life after laparoscopic surgery: evidence-based guidelines o f the European Association for Endoscopic Surgery. Surgical Endoscopy 2004; 18: 879-897. Engel SG, Crosby RD, Kolotkin RL, Hartley GG, Williams GR, Wonderlich SA, Mitchell JE. The Impact of Weight Loss and Regain on Obesity-Specific Quality of Life: Mirror Image or Differential Effect. Obesity Research. 2003;11:1207-1213.
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Gadde KM, Franciscy DM, Wagner HR, Krishnan RR. Zonisamide for weight loss in obese adults. Journal of the American Medical Asso ciation. 2003;289:1820-1825. Ballantyne GH. Measuring outcomes following bar iatric surgery: weight loss parameters, improvement in co-morbid conditions, change in q uality of life and patient satisfaction. Obesity Surgery. 2003;13:954-64. de Zwaan M, Mitchell JE, Ho well LM, Monson N, Swan-Kremeier L, Crosby RD, Seim HC. Characteristics of morbidly obese patients before gastric bypass surgery. Comprehensive Psychiatry. 2003;44:428-34. Kolotkin RL, Crosby RD, Williams GR. Assessing weight-related quality of life in obese persons with type 2 diabetes. Diabetes Research and Clinical Practice. 2003;61:125-32. Kolotkin RL, Crosby RD, Pendleton R et al. Health-related quality of life in patients seeking gastric bypass surgery vs. non-treatment-seeking controls. Obesity Surgery. 2003;13:371-7. Heshka, S., Anderson, J. W., Atkinson, R. L., Greenway, F. L., Hill, J.O., Phinney, S.D., Kolotkin, R. L., Miller-Kovach, K., and P i-Sunyer, F.X. Weight loss with self-help compared with a structured commercial program. Journal of the American Medical Association. 2003;289:1792-1798. de Zwaan M, Mitchell JE, Ho well LM, Monson N, Swan-Kremeier L, Roerig JL, Kolotkin RL, Crosby RD. Two measures of health-related quality of life in mor bid obesity. Obesity Research. 2002;10:1143-51. Dymek MP, Le Grange D, Neven K, Alverdy J. Quality of life after gastric bypass surgery: a cross-sectional study. Obesity Research. 2002;10:1135-42. Scholz GH, Flehmig G, Kahl Y, Gutknecht D, Schmidt U, Tolkmitt S, Kohler-Braunig K, Gabriel C, Dommel S, Krist H, Scholz M. [Proper Weight Loss with Intelligence (MIRA). 2 programs for weight reduction in general practice t rial]. MMW Fortschr Med. 2002;144:28-32. In German. Kolotkin RL, Crosby RD, Williams GR. Health-related quality of life varies among obese subgroups. Obesity Research. 2002;10:748-756. Fontaine KR. Health-related quality of life among o bese subgroups: Editorial. Obesity Research. 2002;10:854-855. Teixeira PJ, Going SB, Houtkooper LB, Cussler EC, Martin CJ, Metcalfe LL, Finkenthal NR, Blew RM, Sardinha LB, Lohman TG: Weight loss readiness in middle-aged women: psychosocial predictors of success for behavioral weight reduction. Journal of Behavioral Medicine. 2002;25: 499-523.
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Wadden TA, Phelan S. Assessment of quality of life in obese individuals. Obesity Research. 2002;10 Suppl 1:50S-7S. Kolotkin RL, Crosby RD, Williams GR et al. The relationship between health-related quality of life and weight loss. Obesity Research. 2001;9:564-571. Kolotkin RL, Meter K, Williams GR. Quality of life and obesity. Obesity Reviews. 2001;2:219-229. Samsa GP, Kolotkin RL, Williams GR et al. E ffect of moderate weight loss on healthrelated quality of life: an analysis of combined data from 4 randomized trials of sibutramine vs. placebo. American Journal of Managed Care. 2001;7:875-883. Fujioka K, Seaton TB, Rowe E, et.al. Weight loss with sibutramine improves glycemic control and other metabolic parameters in obese patients with type 2 diabetes mellitus. Diabetes Obesity and Metabolism. 2000;2:175-184.
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