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Allied health article

Two-year changes in health-related quality of life in gastric bypasspatients compared with severely obese controls

Ronette L. Kolotkin, Ph.D.a,b, Ross D. Crosby, Ph.D.c,d, Richard E. Gress, M.A.e,Steven C. Hunt, Ph.D.e, Ted D. Adams, Ph.D.e,

aObesity and Quality of Life Consulting, Durham, North CarolinabDepartment of Community and Family Medicine, Duke University Medical Center, Durham, North Carolina

cNeuropsychiatric Research Institute, Fargo, North DakotadDepartment of Neuroscience, University of North Dakota School of Medicine, Fargo, North Dakota

eCardiovascular Genetics Division, University of Utah School of Medicine, Salt Lake City, Utah

Received May 3, 2008; revised January 12, 2009; accepted January 17, 2009

bstract Background: Few weight loss surgery trials have evaluated the changes in health-related qualityof life (HRQOL) relative to obese individuals not participating in weight loss interventions. In aprospective study at a bariatric surgery practice, we evaluated the 2-year changes in HRQOL in gastricbypass patients compared with 2 severely obese groups who did not undergo surgical weight loss.Methods: A total of 308 gastric bypass patients were compared with 253 individuals who soughtbut did not undergo gastric bypass and 272 population-based obese individuals using the weight-related (Impact of Weight on Quality of Life-Lite) and general (Medical Outcomes Study 36-itemShort-Form Health Survey) HRQOL questionnaires at baseline and 2 years of follow-up.Results: The percentage of weight loss was 34.2% for the gastric bypass and 1.4% for the no gastricbypass groups, with a .5% gain for population-based obese group. Both measures of HRQOL showedgreater improvements for the gastric bypass group, even after controlling for baseline differences. Effectsizes for changes in physical and weight-related HRQOL were very large for gastric bypass, but smallto medium for the 2 comparison groups. Effect sizes for changes in the psychosocial aspects of HRQOLwere moderate to very large for gastric bypass, but small for the 2 comparison groups. Of the gastricbypass patients, 97% had meaningful improvements in the Impact of Weight on Quality of Life-Lite totalscore compared with 43% of the no gastric bypass group and 30% of the population-based obese group.Conclusion: Dramatic improvements had occurred in weight-related and physical HRQOL forgastric bypass patients at 2 years after surgery compared with 2 severely obese groups who had notundergone surgery. These results support the effectiveness of gastric bypass surgery in improvingpatients’ HRQOL. (Surg Obes Relat Dis 2009;5:250–256.) © 2009 American Society for Metabolicand Bariatric Surgery. All rights reserved.

eywords: Gastric bypass surgery; Health-related quality of life; HRQOL; Cohort trial; Impact of Weight on Quality of

Surgery for Obesity and Related Diseases 5 (2009) 250–256

Life-Lite; IWQOL-Lite; Medical Outcomes Study 36-item Short-Form Health Survey; SF-36

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Weight loss surgery has been associated with major andurable reductions in excess body weight [1,2], total mor-ality [3,4], co-morbid conditions [1,5,6], and improvementsn health-related quality of life (HRQOL) [7–9]. A number

Supported by a grant from the National Institute of Arthritis, Diabetes,igestive and Kidney Diseases (grant R01 DK-55006-06) and grant M01-R00064 from the National Center for Research Resources.

bReprints not available from the authors.

550-7289/09/$ – see front matter © 2009 American Society for Metabolic and Boi:10.1016/j.soard.2009.01.009

f controlled trials have been designed to compare variousariatric surgery procedures with each another [10–13], butew have investigated the HRQOL outcomes in patientsndergoing weight loss surgery relative to nonsurgicallyreated obese individuals.

The Swedish Obese Subjects study, a prospective non-andomized intervention trial, compared obese individualsbody mass index [BMI] �34 kg/m2) undergoing 3 types of

ariatric surgery with nonsurgically treated individuals un-

ariatric Surgery. All rights reserved.

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251R. L. Kolotkin et al. / Surgery for Obesity and Related Diseases 5 (2009) 250–256

ergoing conventional weight loss treatment [14]. HRQOL,ssessed using a battery of general and obesity-specificeasures, improved dramatically in the surgical patients,ith only minor fluctuations in HRQOL scores observed in

he controls. In a randomized controlled trial by O’Brien etl. [15], patients with BMI of 30–35 kg/m2 were randomlyssigned to either laparoscopic adjustable gastric banding orvery-low-calorie diet that included pharmacotherapy and

ifestyle change. At 2 years of follow-up, the patients whoad undergone surgery reported improved general HRQOLn all 8 domains of the HRQOL questionnaire. In contrast,he nonsurgical patients reported improvements in 3 do-ains (i.e., physical functioning, vitality, and mental

ealth).The present study was a prospective 2-year, cohort study

omparing patients who had undergone Roux-en-Y gastricypass surgery with 2 groups of severely obese individualsho did not undergo weight loss surgery—(1) individualsho sought gastric bypass surgery but did not undergo the

urgery, and (2) severely obese community subjects derivedrom a population study. The objective was to evaluate the-year changes in HRQOL in the gastric bypass patients rela-ive to the 2 comparison groups, thus adding to the sparse datarom prospective trials investigating the HRQOL outcomes inastric surgery patients versus obese individuals not enrolled inurgical weight loss interventions.

ethods

articipants

The study participants were recruited for the Utah Obe-ity Study [16], an ongoing, prospective study comparingastric bypass surgery patients with individuals who soughtut did not have gastric bypass surgery as well as severelybese subjects randomly chosen from a population databaseepresenting �1 million first-degree relatives from 120,000tah families [17–19]. The enrolled sample sizes wereased on achieving adequate statistical power to detectlinically meaningful differences between groups in weightoss and changes in medical co-morbidities at 2 years ofollow-up [16]. A total of 421 gastric bypass surgery pa-ients, 405 individuals who sought but did not undergo theurgery, and 319 severely obese population-based subjectsompleted the baseline HRQOL assessments. The partici-ants included in the present study were all those who hadRQOL assessments at both baseline and 2 years of fol-

ow-up (308 gastric bypass patients, 253 individuals whoought but did not undergo gastric bypass surgery, and 272opulation-based obese subjects).

Patients seeking gastric bypass surgery were recruitedrom a partnership of bariatric surgeons of the Rocky Moun-ain Associated Physicians (Salt Lake City, UT). Gastricypass participants had a reported BMI of �40 kg/m2 or a

MI of �35 kg/m2 and 2 co-morbidities. These primarily p

ncluded cardiovascular disease, sleep apnea, uncontrolledype 2 diabetes, or weight-induced physical problems thatnterfered with daily functioning. The exclusion criteria forll study participants included previous gastric surgery foreight loss, gastric or duodenal ulcers in the previous 6onths, active cancer within the past 5 years (except for

on-melanoma skin cancer), myocardial infarction in therevious 6 months, and history of alcohol or narcotic abuse.

rocedures

The University of Utah institutional review board ap-roved the present study. All participants provided in-ormed consent. On the initial evaluation and again at 2ears, the participants’ height and weight were measured byhe study personnel. The BMI was calculated as kilogramser meters squared. Participants also completed question-aires at baseline and 2 years of follow-up that includedemographic information and 2 measures of HRQOL.

easures

The first measure used was the Impact of Weight on Qualityf Life-Lite (IWQOL-Lite). The IWQOL-Lite [20] is a 31-tem measure of weight-related quality of life. It has 5 domaincores (physical function, self-esteem, sexual life, public dis-ress, and work) and a total score. The scores for all domainsnd the total score range from 0 to 100, with lower scoresndicating greater impairment. The IWQOL-Lite has demon-trated excellent reliability and validity [20,21].

The Medical Outcomes Study 36-item Short-Formealth Survey (SF-36) [22] is a 36-item measure of generalRQOL, consisting of 8 subscales (physical functioning,

ole physical, bodily pain, general health, vitality, socialunctioning, role emotional, and mental health) and 2 sum-ary scores (physical component summary [PCS] and men-

al component summary [MCS]). The 2 summary scoresepresent independent (orthogonal) indexes using a factornalysis of the subscale scores from the Medical Outcomestudy data [22]. The scores on all subscales range from 0 to00, with 100 representing the best HRQOL. The scores forhe PCS and MCS are norm based, with a mean of 50 andtandard deviation of 10, with greater scores representingetter HRQOL. Estimates of internal consistency for theF-36 have typically exceeded .80 for all subscales acrossiverse patient groups [23,24].

tatistical analysis

The statistical analyses were restricted to those partici-ants providing both baseline and 2-year follow-up HRQOLssessments for at least 1 IWQOL-Lite or SF-36 scale. Theaseline characteristics of the groups were compared usinghi-square analysis for categorical measures and analysis ofariance for continuous measures, with a 2-tailed alpha of05. Post hoc tests for categorical measures were done using

airwise Bonferroni-corrected [25] chi-square comparisons

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252 R. L. Kolotkin et al. / Surgery for Obesity and Related Diseases 5 (2009) 250–256

alpha � .05/3 � .017) and for continuous measures wereone using Tukey’s honestly significant difference [26] toontrol for multiple comparisons. The baseline HRQOLcores of the groups were compared using analysis of co-ariance, controlling for BMI, gender, and age. The groupsere compared for changes in HRQOL at 2 years of fol-

ow-up using analysis of covariance, controlling for base-ine score, gender, baseline BMI, and age using a Bonfer-oni-corrected 2-tailed alpha of .003 (.05/16) to control forultiple comparisons. Pair-wise post hoc comparisons were

ased on covariate-adjusted Bonferroni-corrected contrastssing a significance of .001 (.003/3). Within-group effectizes were calculated as the difference between the scores athe endpoint and baseline, divided by the baseline standardeviation. Additionally, we computed the number and per-entage of participants in each group that demonstratedeaningful improvement in the IWQOL-Lite total score

sing the algorithm described by Crosby et al. [27]. Usinghis algorithm, scores have shown meaningful improvementf they have increased 7–12 points, depending on the base-ine severity. The percentage of patients demonstratingeaningful improvement/no change/deterioration was com-

ared across groups using chi-square analysis. Logistic re-ression analysis was used to compare the percentage ofatients with meaningful improvement, controlling for-year changes in BMI. All analyses were conductedsing Statistical Package for Social Sciences, version6.0.1 (SPSS, Chicago, IL) [28].

esults

emographic and weight characteristics

Table 1 lists the baseline demographic and weight char-cteristics by group. Those who sought but did not undergourgery were less likely to be married than were the surgeryatients (51.7% versus 67.6%). However, they did not differrom the surgery patients in terms of the other demographicnd weight characteristics. In contrast, the obese popula-

able 1aseline characteristics stratified by group

haracteristic Gastric bypasssurgery (n � 308)

Seeking but didundergo surgery

emale (n) 256 (83.1) 212 (83.8)ge (yr) 46.4 � 10.6* 46.5 � 11.1*arried (n) 192 (67.6)* 104 (51.7)†

hite (n) 275 (89.3)* 233 (91.2)*ducation (yr) 14.1 � 2.2 14.1 � 2.4eight (lb) 290.8 � 61.3* 282.7 � 56.7*

MI (kg/m2) 47.1 � 7.7* 46.0 � 7.5*

BMI � body mass index.Data presented as mean � standard deviation or numbers, with percentCell entries with common superscripts (e.g. *, *, *) are not statistically dif

F test) or Bonferroni (�2) correction. Cell entries without common supers

ukey’s honestly significant differences (F test) or Bonferroni (�2) correction.

ion-based subjects were older, weighed less, and had areater proportion of whites than either the surgery patientsr those who sought but did not undergo surgery. Theroups did not differ significantly (P � .05) in the baselinerevalence rates of hypertension, dyslipidemia, diabetes,oronary heart disease, or cerebrovascular disease.

aseline HRQOL

The baseline comparisons between groups of theWQOL-Lite and SF-36 scores adjusted for BMI, gender,nd age are presented in Table 2. No differences were foundt baseline between the gastric bypass patients and thoseho sought but did not undergo surgery. However, bothroups who sought gastric bypass were more impaired thanhe population-based obese comparison group on all do-ains of both HRQOL measures.

-Year follow-up rates

The 2-year HRQOL assessments (IWQOL-Lite and/orF-36) were obtained for 308 surgery patients (73.2%), 25362.5%) individuals who sought but did not undergo surgery,nd 272 (85.3%) obese community participants (�2

(2) � 36.42,� .001). The Bonferroni-corrected post hoc comparisons

evealed that the follow-up rates were significantly greateror the obese community participants than for the surgeryatients, which were, in turn, significantly greater than theollow-up rates for those who sought but did not undergourgery. The participants who failed to complete the 2-yearssessment were younger, less likely to be married, moreikely to be a minority, had had fewer years of education,ad had a greater BMI, and had reported poorer quality ofife at baseline on most IWQOL-Lite (all except sexual life)nd SF-36 (all except physical function, role physical, vi-ality, and PCS) scales.

eight loss at 2 years

The percentage of weight loss at 2 years among theurgery patients averaged 34.2% � 10.0% (range 65.4%

53)Population-basedobese (n � 272)

Significance

209 (76.8) �2(2) � 5.26, P � .072

51.2 � 10.8† F(2, 830) � 17.68, P �.001174 (71.0)* �2

(2) � 20.00, P �.001265 (97.4)† �2

(2) � 14.59, P �.00113.9 � 2.3 F(2, 710) � 0.86, P � .423

268.6 � 52.8† F(2, 819) � 10.85, P �.00143.8 � 6.3† F(2, 830) � 16.28, P �.001

parentheses.rom each other (P � .05) based on Tukey’s honestly significant differencese.g. *, †, ‡) are statistically different from each other (P � .05) based on

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253R. L. Kolotkin et al. / Surgery for Obesity and Related Diseases 5 (2009) 250–256

oss to 1.0% gain) compared with 1.4% � 8.6% (range1.7% loss to 20.3% gain) for individuals who sought butid not undergo surgery and a .5% � 9.3 gain (range 57.4%oss to 27.0% gain) for the obese population-based partici-ants [F(2,802) � 1235.54, P � .001].

hanges in HRQOL at 2 years

The 2-year changes in the IWQOL-Lite and SF-36 scoresy group are presented in Table 3. Gastric bypass patientsad significantly greater improvement compared with bothhose who sought but did not undergo surgery and theopulation-based obese individuals on all measures. TheRQOL changes in the group who sought but did notndergo surgery were comparable to those in the popula-ion-based obese group, except for the IWQOL-Lite sexualife and work domains, in which greater improvement wasbserved in the group that sought but did not undergourgery. Within-group effect size changes in the surgeryroup for the IWQOL-Lite ranged from 1.62 (sexual life) to.31 (total score) and for the SF-36 ranged from .60 (rolemotional) to 2.04 (physical functioning).

eaningful changes in IWQOL-Lite total score

Of the surgery patients, 97% experienced meaningfulmprovements compared with only 43% of those whoought but did not undergo surgery and 30% of the popu-ation-based obese individuals [�2

(4) � 299.20, P � .001].

able 2aseline IWQOL-Lite and SF-36 scores by group adjusted for BMI, gend

uestionnaire Gastric bypass surgery(n � 273–303)

Seeking but dsurgery (n �

WQOL-Lite scorePhysical function 28.7 � 18.7* 30.9 � 21.1*Self-esteem 24.9 � 20.6* 26.8 � 22.5*Sexual life 40.1 � 29.6* 45.2 � 33.0*Public distress 41.7 � 23.1* 43.0 � 25.5*Work 47.9 � 25.5* 48.5 � 27.0*Total 33.9 � 16.2* 35.9 � 19.1*

F-36 scorePhysical functioning 37.8 � 22.3* 41.5 � 24.4*Role physical 34.9 � 35.8* 38.1 � 39.5*Bodily pain 42.3 � 21.9* 41.9 � 21.7*General health 45.1 � 14.1* 45.4 � 15.0*Vitality 26.9 � 17.1* 28.1 � 19.6*Social functioning 52.0 � 25.3* 54.0 � 27.2*Role emotional 51.6 � 42.6* 47.9 � 43.0*Mental health 61.8 � 18.6* 60.0 � 20.2*PCS 31.6 � 9.1* 33.1 � 9.5*MCS 42.9 � 11.3* 41.8 � 11.9*

IWQOL-Lite � Impact of Weight on Quality of Life-Lite; SF-36 � MediCS � physical component summary; MCS � mental component summaData presented as adjusted mean � standard deviation.Cell entries with common superscripts (e.g. *, *, *) are not statistically di

ith P � .017. Cell entries without common superscripts (e.g. *, †, ‡) arorrected contrasts with P � .017.

his difference remained significant (P � .003) after con- t

rolling for the 2-year changes in BMI. No surgery patientseported meaningful deteriorations in the IWQOL-Lite totalcore during the 2-year period compared with nearly 1 in 5f the group that sought but did not undergo surgery18.9%) and the population-based obese group (17.2%).

iscussion

Quality of life is “an essential parameter in measuringhe effectiveness of bariatric surgery and should be assessedbjectively as a valid outcome measure in clinical trials”29]. The results of the present study add to the sparseublished data on HRQOL outcomes in prospective trials ofariatric surgery versus nonsurgically treated obese groups14,15] and is unique in that 2 separate, severely obeseomparison groups were used, neither of which underwenteight loss surgery. The group that sought but did notndergo surgery was more similar to the surgical group ataseline (because both groups had qualified for and desiredurgery) and provides a direct test of the effectiveness ofastric bypass surgery on HRQOL. This group did not differrom the surgical group with respect to baseline HRQOLnd measured subject characteristics, except for maritaltatus. The severely obese community comparison groupas randomly selected from a population study and thusas representative of the general population of severelybese individuals not seeking bariatric surgery. Although

age

undergo2)

Population-based obese(n � 241–271)

Significance

47.1 � 20.7† F(2, 817) � 77.53, P �.00144.2 � 25.2† F(2, 817) � 61.61, P �.00164.9 � 29.2† F(2, 733) � 43.68, P �.00158.1 � 24.5† F(2, 816) � 47.40, P �.00166.0 � 23.8† F(2, 805) � 43.00, P �.00152.7 � 19.1† F(2, 813) � 95.51, P �.001

56.3 � 22.7† F(2, 810) � 56.28, P �.00157.5 � 39.2† F(2, 816) � 27.20, P �.00156.5 � 22.3† F(2, 814) � 39.57, P �.00153.6 � 16.3† F(2, 814) � 26.33, P �.00140.4 � 20.3† F(2, 814) � 40.61, P �.00170.9 � 24.3† F(2, 814) � 42.68, P �.00164.1 � 39.9† F(2, 816) � 10.34, P �.00169.2 � 18.6† F(2, 814) � 17.57, P �.00139.0 � 9.6† F(2, 809) � 51.67, P �.00147.1 � 11.4† F(2, 809) � 15.09, P �.001

comes Study 36-item Short-Form Health Survey; BMI � body mass index;

rom each other based on covariate-adjusted Bonferroni-corrected contraststically different from each other based on covariate-adjusted Bonferroni-

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254 R. L. Kolotkin et al. / Surgery for Obesity and Related Diseases 5 (2009) 250–256

atch the gastric bypass seekers on a number of variables,he use of this group allowed us to compare the changes inRQOL at 2 years after surgery with those reported by a

able 3wo-year changes in IWQOL-Lite and SF-36 scores

uestionnaire Gastric bypass surgery(n � 260–298)

Seeking but dsurgery (n �

WQOL-Lite scorePhysical function

Mean � SD 58.8 � 20.6* 13.8 � 25.8†

Effect size 3.13 0.65Self-esteem

Mean � SD 56.7 � 26.5* 13.1 � 23.1†

Effect size 2.75 0.58Sexual life

Mean � SD 47.8 � 31.8* 7.2 � 29.4†

Effect size 1.62 0.22Public distress

Mean � SD 52.2 � 23.4* 11.6 � 26.0†

Effect size 2.25 0.45Work

Mean � SD 44.0 � 26.8* 9.5 � 25.9†

Effect size 1.73 0.35Total

Mean � SD 54.0 � 19.4* 12.0 � 21.7†

Effect size 3.31 0.63F-36 scorePhysical functioning

Mean � SD 45.4 � 26.1* 6.7 � 22.0†

Effect size 2.04 0.28Role physical

Mean � SD 47.4 � 45.5* 11.6 � 42.8†

Effect size 1.33 0.29Bodily pain

Mean � SD 27.4 � 25.4* 4.3 � 23.0†

Effect size 1.25 0.20General health

Mean � SD 22.6 � 16.9* 5.4 � 17.5†

Effect size 1.59 0.36Vitality

Mean � SD 31.6 � 24.0* 6.2 � 20.6†

Effect size 1.84 0.32Social functioning

Mean � SD 29.5 � 28.4* 6.0 � 29.0†

Effect size 1.17 0.22Role emotional

Mean � SD 25.5 � 50.3* 12.8 � 51.7†

Effect size 0.60 0.29Mental health

Mean � SD 14.8 � 19.6* 2.4 � 19.8†

Effect size 0.80 0.12PCS

Mean � SD 16.9 � 10.0* 2.7 � 9.0†

Effect size 1.88 0.29MCS

Mean � SD 7.0 � 13.1* 2.4 � 12.6†

Effect size 0.62 0.20

Abbreviations as in Table 2.Data presented as mean � standard deviation change from baseline andCell entries with common superscripts (e.g. *, *, *) are not statisticall

ontrasts with P � .017. Cell entries without common superscripts (e.g.onferroni-corrected contrasts with P � .017.

eneral sample of obese individuals not seeking obesity s

urgery. The significant 2-year postoperative surgical dif-erences in HRQOL relative to the 2 comparison groupseinforce the findings of the effectiveness of gastric bypass

ndergo4)

Population-based obese(n � 226–262)

Significance

4.9 � 17.6† F(2, 797) � 445.68, P �.0010.24

8.3 � 18.4† F(2, 797) � 341.60, P �.0010.34

5.0 � 26.4‡ F(2, 686) � 147.47, P �.0010.17

4.6 � 19.3† F(2, 796) � 336.38, P �.0010.19

4.6 � 20.4‡ F(2, 788) � 207.69, P �.0010.19

5.5 � 15.1† F(2, 797) � 463.74, P �.0010.29

0.8 � 21.2† F(2, 743) � 233.72, P �.0010.04

2.9 � 39.8† F(2, 752) � 68.88, P �.0010.07

�0.4 � 20.4† F(2, 752) � 92.21, P �.001�0.02

2.1 � 13.9† F(2, 751) � 117.97, P �.0010.13

4.7 � 16.4† F(2, 751) � 122.90, P �.0010.23

1.7 � 23.9† F(2, 752) � 61.56, P �.0010.07

6.9 � 42.4† F(2, 752) � 11.99, P �.0010.17

1.3 � 16.5† F(2, 752) � 41.26, P �.0010.7

0.4 � 8.3† F(2, 741) � 217.62, P �.0010.04

1.7 � 10.5† F(2, 741) � 13.99, P �.0010.15

-group effect size.ent from each other based upon covariate-adjusted Bonferroni-correctedare statistically different from each other based upon covariate-adjusted

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urgery on improving HRQOL and might have implications

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255R. L. Kolotkin et al. / Surgery for Obesity and Related Diseases 5 (2009) 250–256

or policy development regarding reimbursement. Thenique inclusion of the 2 comparison groups has providedn opportunity to test what happens to the HRQOL ofeverely obese individuals if they are left to their ownevices regarding weight loss treatment and directly ad-resses the beneficial effects of gastric bypass surgery ver-us no surgical intervention.

Statistically significant improvements were observed inll aspects of HRQOL for the surgery patients at 2 yearsompared with the group that sought but did not undergourgery. In addition, 97% of the surgical patients experi-nced meaningful improvements in the IWQOL-Lite totalcore compared with 43% of the group that did not undergourgery. Dramatic changes in HRQOL occurred at 2 yearsor the surgical patients. For example, the IWQOL-Lite totalcore changed �3 standard deviations, the SF-36 PCShanged nearly 2 standard deviations, and the SF-36 MCShanged just more than one half a standard deviation. Inomparison, the improvements in HRQOL were much moreodest in the group that did not undergo surgery. The

WQOL-Lite total score changed a little more than one halfstandard deviation, and the SF-36 PCS and MCS scores

hanged less than one third of a standard deviation. Thereater changes observed in the weight-related measureIWQOL-Lite) than in the general measure of HRQOLSF-36) are consistent with previous reports of the greaterensitivity of disease-specific measures of HRQOL [30].

We also found large and statistically significant differ-nces between the gastric bypass surgery patients and theopulation-based severely obese comparison group at 2ears. For this group, the 2-year changes in HRQOL wereuite modest, in stark contrast to the dramatic changesbserved in the surgical group. The IWQOL-Lite total scorehanged less than one third of a standard deviation, and theF-36 PCS and MCS scores showed almost no change fromaseline.

Both comparison groups experienced some improvementn HRQOL, perhaps because of their participation in aesearch study. It is likely that the greater changes observedn the group that sought but did not undergo surgery versushe population-based obese group were a result of theiroorer baseline HRQOL, which allowed more opportunityor improvement. Our finding of better HRQOL at baselinen the population-based obese group than in the subjectsho sought but did not undergo surgery is consistent withrevious research comparing the HRQOL of bariatric sur-ery seekers and obese community volunteers [31]. Weave speculated that the presence of a better HRQOLmong the population-based participants might account forheir lack of interest in seeking bariatric surgery despite thelinically severe obesity. We can also speculate about whyhe group that sought but did not undergo gastric bypass didot undergo the surgery. In most cases, these participantsndicated that their insurance companies would not cover

he procedure. However, some participants who initially t

ere denied coverage by their insurance company later paidor the surgery out of their own pocket. Thus, it is possiblehat socioeconomic factors might have played a role inetermining why some seekers of gastric bypass surgery didot undergo the surgery (although no differences wereound with respect to the years of education between the 2roups seeking surgery). Furthermore, the groups mightave differed with respect to insurance company require-ents regarding the necessity of undergoing behavioral or

ther interventions before approval for surgery, as well asther variables not assessed in the present study (e.g., theresence of social support). It is possible that some partic-pants in the group that sought but did not undergo surgeryhanged their minds about the surgery. It is also possiblehat the groups differed at baseline in the rates of medical orsychiatric co-morbidities that were not measured and thathese differences could have influenced the results. How-ver, we lacked the data that would allow us to address thesessues.

One strength of the present study was that both generalnd weight-related measures were used to assess theRQOL as recommended in a critical review of controlledeight loss trials [32]. Of the 2 prospective, controlled trialsf bariatric surgery published, the Swedish Obese Subjectstudy also used both types of HRQOL measures [14], andhe study by O’Brien et al. [15] used only a general mea-ure. However, the follow-up rates were better in the lattertudy (98% of 40 surgical patients and 83% of 40 nonsur-ical patients at 2 years) and in the Swedish Obese Subjectstudy (98% of 487 surgical patients and 84% of 487 non-urgical patients at 2 years) than in the present study (73.2%f surgical patients, 62.5% of individuals in the group thatought but did not undergo surgery, and 85.3% of theopulation-based obese individuals). Incomplete participa-ion in the follow-up assessments could have resulted inias. Additionally, differences were present in subject char-cteristics and baseline HRQOL scores between the partic-pants who completed the follow-up HRQOL assessmentsnd those who did not, creating a bias in favor in favor ofhe participants with a better baseline HRQOL and lowerMI, as well as those who were older, married, more edu-ated, and white. It is also unknown whether participants inhe comparison groups sought nonsurgical weight loss treat-ent during the course of the present study, which, if they

ad, could have contributed to the improvement in HRQOL.

onclusion

At 2 years of follow-up, dramatic improvements in 2ypes of HRQOL were found for patients who had under-one gastric bypass surgery compared with individuals whoought but did not undergo gastric bypass surgery andeverely obese volunteers from a population sample. Patientsndergoing gastric bypass surgery lost an average of 34.2% of

heir body weight. The large weight reduction was likely re-

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256 R. L. Kolotkin et al. / Surgery for Obesity and Related Diseases 5 (2009) 250–256

ponsible for the observed improvements in HRQOL. How-ver, it is possible that similar changes in HRQOL would occurn patients achieving this same degree of weight loss throughonsurgical means.

isclosures

R. L. Kolotkin received compensation in her role asonsultant on the National Institute of Diabetes and Diges-ive and Kidney Diseases grant, and she receives royaltiesrom Duke University for the use of the IWQOL-Lite ques-ionnaire.

eferences

[1] Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: asystematic review and meta-analysis. JAMA 2004;292:1724–37.

[2] O’Brien PE, McPhail T, Chaston TB, Dixon JB. Systematic review ofmedium-term weight loss after bariatric operations. Obes Surg 2006;16:1032–40.

[3] Adams TD, Gress RE, Smith SC, et al. Long-term mortality aftergastric bypass surgery. N Engl J Med 2007;357:753–61.

[4] Sjostrom L, Narbro K, Sjostrom CD, et al. Effects of bariatric surgeryon mortality in Swedish obese subjects. N Engl J Med 2007;357:741–52.

[5] Pories WJ, Swanson MS, MacDonald KG, et al. Who would havethought it? An operation proves to be the most effective therapy foradult-onset diabetes mellitus. Ann Surg 1995;222:339–52.

[6] Sjostrom L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, andcardiovascular risk factors 10 years after bariatric surgery. N EnglJ Med 2004;351:2683–93.

[7] Dixon JB, O’Brien PE. Changes in comorbidities and improvementsin quality of life after LAP-BAND placement. Am J Surg 2002;184:51S–54S.

[8] O’Brien PE, Dixon JB, Brown W, et al. The laparoscopic adjustablegastric band (Lap-Band): a prospective study of medium-term effectson weight, health and quality of life. Obes Surg 2002;12:652–60.

[9] Wadden TA, Sarwer DB, Fabricatore AN, Jones L, Stack R, WilliamsNS. Psychosocial and behavioral status of patients undergoing bari-atric surgery: what to expect before and after surgery. Med Clin NorthAm 2007;91:451–69, xi–xii.

10] Sugerman HJ, Starkey JV, Birkenhauer R. A randomized prospectivetrial of gastric bypass versus vertical banded gastroplasty for morbidobesity and their effects on sweets versus non-sweets eaters. AnnSurg 1987;205:613–24.

11] Nguyen NT, Goldman C, Rosenquist CJ, et al. Laparoscopic versusopen gastric bypass: a randomized study of outcomes, quality of life,and costs. Ann Surg 2001;234:279–91.

12] Hell E, Miller KA, Moorehead MK, Norman S. Evaluation of healthstatus and quality of life after bariatric surgery: comparison of stan-dard Roux-en-Y gastric bypass, vertical banded gastroplasty andlaparoscopic adjustable silicone gastric banding. Obes Surg 2000;10:214–9.

13] Muller MK, Wenger C, Schiesser M, Clavien PA, Weber M. Qualityof life after bariatric surgery—a comparative study of laparoscopic

banding vs. bypass. Obes Surg 2008;18:1551–7.

14] Karlsson J, Sjostrom L, Sullivan M. Swedish obese subjects(SOS)—an intervention study of obesity: two-year follow-up ofhealth-related quality of life (HRQL) and eating behavior after gastricsurgery for severe obesity. Int J Obes Relat Metab Disord 1998;22:113–26.

15] O’Brien PE, Dixon JB, Laurie C, et al. Treatment of mild to moderateobesity with laparoscopic adjustable gastric banding or an intensivemedical program: a randomized trial. Ann Intern Med 2006;144:625–33.

16] Adams TD, Avelar E, Cloward T, et al. Design and rationale of theUtah obesity study: a study to assess morbidity following gastricbypass surgery. Contemp Clin Trials 2005;26:534–51.

17] Hunt SC, Williams RR, Barlow GK. A comparison of positive familyhistory definitions for defining risk of future disease. J Chronic Dis1986;39:809–21.

18] Williams RR, Hunt SC, Barlow GK, et al. Health family trees: a toolfor finding and helping young family members of coronary andcancer prone pedigrees in Texas and Utah. Am J Pub Health 1988;78:1283–86.

19] Williams RR, Hunt SC, Heiss G, et al. Usefulness of cardiovascularfamily history data for population-based preventive medicine andmedical research (the Health Family Tree Study and the NHLBIFamily Heart Study). Am J Cardiol 2001;87:129–35.

20] Kolotkin RL, Crosby RD, Kosloski KD, Williams GR. Developmentof a brief measure to assess quality of life in obesity. Obes Res2001;9:102–11.

21] Kolotkin RL, Crosby RD. Psychometric evaluation of the Impact ofWeight on Quality Of Life-Lite questionnaire (IWQOL-Lite) in acommunity sample. Qual Life Res 2002;11:157–71.

22] Ware J, Snow K, Kosinski M, Gandek B. SF-36 health survey:manual and interpretation guide. Boston: Health Institute, New En-gland Medical Center; 1993.

23] McHorney CA, Ware JE Jr, Lu JF, Sherbourne CD. The MOS36-item short-form health survey (SF-36): III. Tests of data quality,scaling assumptions, and reliability across diverse patient groups.Med Care 1994;32:40–66.

24] McHorney CA, Ware JE Jr, Raczek AE. The MOS 36-item short-form health survey (SF-36): II. Psychometric and clinical tests ofvalidity in measuring physical and mental health constructs. MedCare 1993;31:247–63.

25] Miller RG. Simultaneous statistical inference. 2nd ed. New York:Springer-Verlag; 1981.

26] Winer BJ. Statistical principles in experimental design. 2nd ed. NewYork: McGraw-Hill; 1971.

27] Crosby RD, Kolotkin RL, Williams GR. An integrated method todetermine meaningful changes in health-related quality of life. J ClinEpidemiol 2004;57:1153–60.

28] SPSS. Statistical package for the social sciences (version 16.0.1).Chicago: SPSS Inc.; 1989–2007.

29] Nguyen N, Varela EJ, Nguyen T, Wilson SE. Quality of life assess-ment in the morbidly obese. Obes Surg 2006;16:531–3.

30] Guyatt GH, Jaeschke R, Feeny DH, Patrick DL. Measurements inclinical trials: Choosing the right approach. In: Spilker B, editor.Quality of life and pharmacoeconomics in clinical trials. 2nd ed.Philadelphia: Lippincott-Raven; 1996. p. 41–8.

31] Kolotkin RL, Crosby RD, Williams GR. Health-related quality of lifevaries among obese subgroups. Obes Res 2002;10:748–56.

32] Maciejewski ML, Patrick DL, Williamson DF. A structured review ofrandomized controlled trials of weight loss showed little improve-ment in health-related quality of life. J Clin Epidemiol 2005;58:

568–78.