6 Quality of Life Summary The primary reasons why obese people attempt to lose weight probably relate to the negative impact that obesity has on their quality of life, i. e., how they feel and func- tion, and the perceived benefits of weight loss treatment. Research on quality of life and obesity is a relatively new field, but the knowledge gained already suggests that measuring the quality of life of obese people can provide new, valuable clinical in- formation. Results: Ten population studies were found in the scientific literature. They used the same instrument for obese individuals and normal weight individuals. Six studies addressed quality of life in people who had visited health services for obe- sity, and four studies compared quality of life with that in patients having other diseases. One large study investigated the effects of weight loss from surgery, and weight loss from nonsurgical methods was addressed in six studies. Quality of life among obese people was clearly lower than that in the general po- pulation as regards physical function, general health status, and vitality (Evidence Grade 1). The situation was worse for women than for men, and was also worse in those with more pronounced obesity, in those with other concurrent disease, and in those who sought treatment (Evidence Grade 2). In many subjects, quality of life was lower in patients with severe obesity than in patients with other severe chronic diseases (Evidence Grade 3). Quality of life improved with weight loss. The more pronounced the weight loss, the better was the quality of life (Evidence Grade 2). With pronounced weight loss (20±25 %), well-being and psychosocial functioning reached a level similar to the remainder of the population (Evidence Grade 2). This degree of improvement could be measured after surgical intervention only where dramatic and permanent weight loss was achieved. Uncertain short-term effects (less than 1 year) on quality of life have been documented with modest weight loss, but the data are insufficient for grading the evidence. Conclusion: Obese people have a lower quality of life than do people of normal weight. With permanent weight loss, such as that achieved by surgical intervention for severe obesity, quality of life improves with the degree of weight loss. 261 Treating and Preventing Obesity. Edited by J. Östman, M. Britton, E. Jonsson Copyright c 2004 WILEY-VCH Verlag GmbH & Co. KgaA, Weinheim ISBN 3-527-30818-0
Transcript
6Quality of Life
Summary
The primary reasons why obese people attempt to lose weight probably relate to thenegative impact that obesity has on their quality of life, i. e., how they feel and func-tion, and the perceived benefits of weight loss treatment. Research on quality of lifeand obesity is a relatively new field, but the knowledge gained already suggests thatmeasuring the quality of life of obese people can provide new, valuable clinical in-formation.
Results: Ten population studies were found in the scientific literature. They usedthe same instrument for obese individuals and normal weight individuals. Sixstudies addressed quality of life in people who had visited health services for obe-sity, and four studies compared quality of life with that in patients having otherdiseases. One large study investigated the effects of weight loss from surgery,and weight loss from nonsurgical methods was addressed in six studies.
Quality of life among obese people was clearly lower than that in the general po-pulation as regards physical function, general health status, and vitality (EvidenceGrade 1). The situation was worse for women than for men, and was also worse inthose with more pronounced obesity, in those with other concurrent disease, andin those who sought treatment (Evidence Grade 2). In many subjects, quality oflife was lower in patients with severe obesity than in patients with other severechronic diseases (Evidence Grade 3).
Quality of life improved with weight loss. The more pronounced the weight loss,the better was the quality of life (Evidence Grade 2). With pronounced weight loss(20±25 %), well-being and psychosocial functioning reached a level similar to theremainder of the population (Evidence Grade 2). This degree of improvementcould be measured after surgical intervention only where dramatic and permanentweight loss was achieved. Uncertain short-term effects (less than 1 year) on qualityof life have been documented with modest weight loss, but the data are insufficientfor grading the evidence.
Conclusion: Obese people have a lower quality of life than do people of normalweight. With permanent weight loss, such as that achieved by surgical interventionfor severe obesity, quality of life improves with the degree of weight loss.
261
Treating and Preventing Obesity. Edited by J. Östman, M. Britton, E. JonssonCopyright � 2004 WILEY-VCH Verlag GmbH & Co. KgaA, WeinheimISBN 3-527-30818-0
6.1Introduction
The term ™qualityof life , like ™health ,is multifaceted and cannot be specificallydefined. Although both concepts reflect different aspects of well-being, quality oflife has a substantially broader context. The concept of health-related quality oflife involves a pragmatic distinction and applies mainly to function and well-being during sickness, ill health, and treatment. The models for concepts and mea-sures range from disease-specific to general aspects, from physical to psychologicalhealth, and from functional impairment to well-being (Table 6.1).
Measuring and evaluating aspects of quality of life and obesity were initially dis-cussed by the research community in the late 1980s [26]. Physical, psychological,and psychosocial aspects were addressed. Among other issues, attention wasgiven to problems involving prejudice and discrimination against obese people.One approach discussed was that research on quality of life should contribute to-ward changing public attitudes toward obesity, e. g., moving away from placingguilt on patients and moving toward effective health service interventions.
The previous, rather unilateral focus on weight, BMI, and the risks of obesity didnot provide sufficient understanding of how an individual's quality of life is af-fected or of the benefits and limitations associated with medical treatment in a pa-tient's life. The things that obese people perceive to be the most important are, onthe one hand, avoiding severe symptoms, hospitalization, and heavy medication,and on the other hand surviving, feeling good, and being able to function indaily life.
In recent decades, reliable methods for measuring quality of life have been de-veloped and tested via international collaboration between physicians and method-ology experts. Standardized questionnaires are now sophisticated enough to mea-sure experiences and draw international comparisons. These questionnaires can beself-administered by patients, following brief instructions, and cover important,well-defined areas such as symptom severity, functional impairment, and physical,psychological, and social well-being. The methods have been sufficiently assessedto permit the development of guidelines for their application and interpretation. Tobe used as an outcome measure, e. g., for obesity, the concept of quality of lifeshould:
� rest on a foundation of patient-based information� be multidimensional and health related� have the capacity to confirm changes in how patients feel and function in daily
life.
262 6 Quality of Life
6.2Methods
This chapter is based on a systematic literature review of studies addressing thequality of life of obese people and the effect that treating obesity has on the qualityof life in adults. All available databases, including PsycInfo, were used to identifyrelevant studies. The search terms used, alone and in combination, were: ™obesityand quality of life, and questionnaire , ™SF-36 , ™mentalhealth , and ™BMIandquality of life . (SF-36 is an established method for measuring quality of life.)The final search was performed in December 2001. Only studies that had usedstandardized methods, described the process used, and reported adequate datawere selected for the final review.
6.3Results
6.3.1Quality of Life in Overweight and Obese People
Table 6.2 presents the 10 population studies that were found in this subject area.The studies were conducted in Europe, Australia, and the United States. Thesame instrument, the SF-36 health questionnaire, was used to measure functionand well-being (Table 6.1). Although the studies reveal differences in design, ma-terial, dropout, etc., they do provide an overview of the situation.
Obese people generally report impaired function and a lower level of well-being,more in a physical than in a psychological sense, than overweight and normalweight groups. Quality of life deteriorates as weight increases. Significant differ-ences are found throughout the ™physicalfunction scale, and mainly reflect im-paired movement and mobility functions in obese people.
Even the ™generalhealth and ™vitality scales, which include physical and psy-chological health, are consistently lower in obese people. Furthermore, the painscale indicates that obese people often have more pain than others. Estimatingthe effect size confirms that these aspects in quality of life are the most impaired[6, 19, 20, 28]. In extreme obesity (BMI � 40), both physical and psychologicalparameters are greatly impaired and differ significantly from all other groups. Incomparisons between extremely obese and normal weight people, the greatest ef-fect is on ™physicalfunction , 1.14 [6], 1.18 [19], and 1.06 [22] (BMI � 35). Otherscales such as ™role function/physical causes , ™pain ,™generalhealth , ™vitality,and ™socialfunction show major to moderate effects.
One study found that the greatest deterioration in quality of life was amongobese women aged 35 through 64 years [19]. Other morbidity and physical inactiv-ity were contributing factors. Each of these factors had a significant impact on im-pairing the quality of life, mainly as regards physical health. Several of the studiesconfirmed this, depending to some extent on the method of analysis and adjust-
2636.3 Results
264 6 Quality of Life
Table 6.1 Health-related quality of life and obesity in population studies (SF-36 Health Questionnaire).
AuthorYearReference
Country Number,Responserate %
Age range,mean ageyears
Women%
Brown WJ et al.1998[2]
Australia 13 43154
45±49dm
100
Brown WJ et al.2000[3]
Australia 14 77943
18±2320
100
Burns CM et al.2001[4]
The Netherlands 4 60144
20±5942
53
Doll HA et al.2000[6]
Great Britain 8 88964
18±6441
56
Fine JT et al.1999[7]
USA 40 09869
46±7158
100
Han TS et al.1998[10]
The Netherlands 4 04150
20±5942
53
Larsson U et al.2002[19]
Sweden 5 63372
16±64dm
51
Le Pen C et al.1998[20]
France 85385
18�dm
45
Richards MM et al.2000[22]
USA 290dm
43dm
65
Sullivan M et al.2001[28]
Sweden 1 69468
18� 51
dm = data missing; HRQL = Health-Related Quality of Life1 PF: Physical Functioning; RP: Role ± Physical; BP: Bodily Pain; GH: General Health;
VT: Vitality; SF: Social Functioning; RE: Role ± Emotional; MH: Mental Health;(±) = significantly poorer quality of life; (�) = significantly better quality of life
Comp: BMI �27 versus BMI 35�PF, RP, BP, GH, VT, SF, RE, MH (±)
MediumComparison between adult sibling pairsreared in the same family where oneis normal weight and one is severelyobese
Comp: age- and gender-matched population normversus BMI 30� PF, RP, BP, GH, VT, SF, RE, MH (±)
MediumBased on Swedish population normfor SF-36, n=8930
ment for the influence of various factors. Doll documented the impact of othermorbidity on lowering the quality of life in both a physical and a psychological con-text [6].
Burns reports on other factors that contribute toward reduction of the quality oflife due to overweight (BMI � 25) [4]. Perceived overweight had a more negativeinfluence on some aspects of quality of life than BMI, adjusted for age and educa-tion. The ™generalhealth and ™vitality scales in both genders and the ™physicalfunction scale in women were significantly lower for those who perceived them-selves as obese. Frequent attempts at dieting during the past 5 years also showed acorrelation with impaired quality of life. Among men, the ™physicalfunction and™rolefunction/emotional causes scales had an impact, and in women a decline in6 of 8 scales was documented, e. g., ™physicalwell-being and ™rolefunction/emo-tional causes . Middle-aged women (40±50 years) with 10 % or more weight gainshowed significantly worse values in the ™physicalfunction , ™generalhealth , and™vitalityscales than groups with less weight gain or weight loss. The findings withregard to weight gain and diminished health status are comparable with Fine'sdocumentation from a large cohort of women aged 46±71 years, who were followedprospectively for 4 years [7]. Weight gain correlated significantly to lower levels of™physicalfunction , ™vitality, and ™pain .Weight loss over the 4-year period wassignificantly associated with improved levels in these three scales.
266 6 Quality of Life
Table 6.2 Health related quality of life and obesity. Differences in the SF-36 scales are expressedin effect sizes: trivial (0 to �0.2), small (0.2 to �0.5), moderate (0.5 to �0.8) and great (0.8�).
Overweightand obesepatientsn�312versusOverweightand obese patientswho did not seektreatmentn�89
Physical Functioning (PF) Moderate Great Small
Role ± Physical (RP) Small Great Small
Bodily Pain (BP) Great Great Moderate
General Health (GH) Small Great Small
Vitality (VT) Great Great Moderate
Social Functioning (SF) Small Moderate Trivial
Role ± Emotional (RE) Trivial Small Trivial
Mental Health (MH) Small Moderate Trivial
The ™psychologicalwell-being scale surprisingly showed similar values amongcountries and degree of overweight, with the exception of extreme obesity. Theresults indicate that psychological stress levels do increase in a linear trendwith increasing weight in the general population, up to the cutoff point for severeobesity. The low level of psychological health status in the extremely obese groupsuggests that there is a BMI level at which psychological well-being begins todeteriorate radically. However, it is uncertain whether the ™psychologicalwell-being scale (in SF-36) is sufficiently sensitive to detect mood problems suchas mild and more severe depression. One of the population studies used astudy-specific measure in addition to SF-36 [20], but it did not improve the re-sults.
6.3.2Studies of Obese People who Seek Treatment
A few studies have reported data to highlight possible differences between obesepeople who seek treatment and population groups. The results point in thesame direction. Fontaine presented data from a well-designed study of 312 patientswho sought treatment for various levels of overweight in comparison with a nor-mal American population (Table 6.3) [8]. The results agree with the pattern de-scribed in the population studies, i. e., the greater the obesity the lower the qualityof life. However, the patients' values are substantially lower with regard to thephysical aspects of quality of life than those presented in corresponding BMIgroups in the population studies. The analyses controlled for other morbidityand sociodemographic variables. A comparison between people seeking treatmentfor obesity and those not seeking treatment showed that the non-seekers had lowervalues on the ™pain ,™vitality, and ™generalhealth scales [9]. Obese patients whoreported pain clearly had worse quality-of-life profiles, even in the other 7 scales,than other patients did [1].
The Swedish Obese Subjects (SOS) study (Chapter 4.6) investigated men withBMI �34 and women with BMI �38, aged 37±57 years, using an extensivebattery of general and obesity-specific instruments that covered all importantaspects of quality of life (Table 6.1). Comparison with a gender- and age-matchedpopulation group without obesity (58 % normal weight, 41.5 % overweight,0.5 % underweight) shows that seekers of care within the framework of theSOS study (11 % obese, 43 % severely obese, 46 % extremely obese) clearly hada worse quality-of-life profile than the normal weight population. This appliedto both men and women (Table 6.4). Obese women showed greater variationsthan the normal population as regards all physical and psychological aspectsexcept ™generalhealth perception , where the differences for men and womenwere similar [14]. The general negative impact of obesity on quality of lifeconfirms earlier comparisons in the SOS study. Functional health (based on theSickness Impact Profile, which measures functional impairment in 12areas) was found to be significantly worse in terms of both physical and psy-chological aspects than that of the normal weight population [28]. Cognitive
2676.3 Results
function, attention, memory, and communication were, however, not worse inobese people. The results agree with earlier data from the first 1743 SOS patients[27].
6.3.3Comparisons with People having other Chronic Disease and Disability
The SOS study also drew comparisons with other groups in health care to betterdescribe the type and extent of problems with obesity. Psychological well-beingwas worse among patients who sought treatment for severe obesity than amongmost other patient groups with chronic conditions, e. g., rheumatoid arthritis, can-cer (2±3 years after diagnosis), or paralysis following spinal cord injury [27]. Moodwas worse among obese people than in people who had survived cancer and was
268 6 Quality of Life
Table 6.3 Health-related quality of life and obesity. Comparison between obese patients (SOS)and normal weight people in the population. Differences expressed in effect sizes:trivial (0 to �0.2), small (0.2 to �0.5), moderate (0.5 to �0.8) and great (0.8�).
AreaEffect sizesObesity versus non-obesity1
Men2 Women2
Eating behaviorRestrained eating Trivial TrivialUncontrolled eating Great GreatSense of hunger Great Great
Psychosocial functionPsychosocial problems Great Great
FunctionFunctional status, total Great GreatGait Moderate GreatHousework Moderate ModerateEmployment Moderate ModerateFree-time/recreation Great GreatSocial interaction Moderate Moderate
General health perceptionCurrent health Great Great
Mental well-beingMood, total Moderate GreatAnxiety Moderate ModerateDepression Moderate GreatSelf-rating Small Great
Quality of life, totalGlobal rating Moderate Great
1 All tests of differences between obesity and non-obesity are significant,except tests for ™restrained eating in men (non-significant)
TFEQ: Three-Factor Eating Questionnaire; OP: Obesity-related Problem scale;OD: Obesity mental Distress scale; SIP: Sickness Impact Profile (5/12 categories);SF-36: Short-Form Health Survey; GHRI: General Health Rating Index;HAD: Hospital Anxiety and Depression scale; MACL: Mood Adjective Check List;SE: Self-Esteem scale
1 OD included at 0, 2, and 10 years2 SF-36 included at 10 years
approximately the same as that among patients who had relapsed to cancer [28].Obese people had the same degree of psychological distress as individuals withspinal cord injury at an early stage (� 2 years after injury). Comparisons of thelevel of mental illness among patients with obesity and other chronic diseases sup-port the conclusion that those who seek treatment for obesity have a markedly di-minished level of psychological well-being [27].
Functional capacity among the earliest patients in the SOS study was comparedto that of cancer survivors [28]. Functional health was found to be significantlyworse when one considered both physical and psychosocial aspects in obese peo-ple. Further analyses show that the functional profile in obesity was comparableto that in subgroups with one or more relapses of cancer, except that mobilitywas better in obese patients. Function was also better than that in patients with per-manently impaired mobility, e. g., that resulting from rheumatoid arthritis andhealed spinal cord injury.
Two other studies addressing similar issues have been published. Fontaine com-pared the influence of pain in obese subjects with data published earlier fromAmerican studies of depression, heart failure, symptomatic HIV, and migraine[8]. Obese people reported significantly more pain than other patient groups, ex-cept for patients with migraine, where the values were similar, even though re-searchers adjusted for other morbidity that might explain the pain problem. How-ever, these results have not been replicated/verified.
Katz presents cross-sectional data concerning the influence of overweight andobesity on quality of life in patients with various chronic diseases [15]. The resultsare from SF-36, which was applied in the largest American primary care study, theMedical Outcomes Study. Of 2931 patients, a little over one third were not over-weight (BMI � 25), a similar number were overweight, while 18 % were obeseand 12 % were severely obese (BMI � 35). A subgroup of non-overweight patientswith mild hypertension was used as a reference group in the analysis. A group ofheart failure patients was also compared. The analyses were controlled for numer-ous demographic and lifestyle variables along with other mental and physical mor-bidity. The findings showed that both overweight and obese individuals had signif-icantly lower values on physical scales in SF-36 than those of the reference group,mainly impaired physical function but also reduced role function on physicalscales and elevated values on the pain scale. Obese patients also had significantlyworse general health and vitality. In severe obesity, role function was impaired foremotional reasons. No differences could be documented in social function or psy-chological well-being. Severely obese people were close to the level of heart failurepatients as regards physical function and vitality, but had higher pain scores. Com-pared to men, women in all overweight groups demonstrated lower values on mostof the scales.
270 6 Quality of Life
6.3.4Specific Psychosocial Problems in Obese Patients
Obese people commonly face prejudicial attitudes in Western cultures, even inhealth services. Discrimination against obese people in working life and in severalother social contexts has been documented [29]. This problem has not received suf-ficient attention and has not been evaluated by standardized measurement meth-ods.
The SOS study integrated psychosocial function in the quality-of-life measure-ments (Figure 6.1). Obesity-related psychosocial problems are related, to differentdegrees, to the level of overweight in men and women [28]. Women report moreproblems in all areas regardless of level of obesity, while men report more prob-lems with increasing obesity. Regardless of gender, social activities in public places,e. g., trying on and purchasing clothing, swimming, etc., present the greatest prob-lems. Even participating in group activities and outdoor life are perceived as prob-lems by many obese people. Background variables found to have an independentrelationship with the measurement scale were, in declining order of importance,previous psychiatric symptomatology, female gender, perceived obesity, joint prob-lems, many dieting attempts, physical inactivity, and angina. These variables, incombination, explained 28 % of the variance in the OP scale (see Chapter 4.6 onsurgical treatment) [13, 27].
2716.3 Results
Private party at home
Party at friends' house
Visiting restaurant
Participating in courses
Traveling on vacation
Trying and buying clothes
Swimming in public
Living with a partner
Troubled by activities listed below:
Obesity-related psychosocial problems – OP
0
Source: Section for Healthcare Research, Sahlgrenska University Hospital, 1998.
25 50 75
Women Men
100
%
Figure 6.1 Obesity-related psychosocial problems in men and women in the SOS study(n=5187). Share troubled (very or somehwat troubled) shown for each item on the OP scale.
6.3.5Effects of Surgery on Quality of Life
A study on quality of life from the SOS intervention study showed dramatic im-provements in quality of life after 6 months for the group receiving surgery,while the control group improved to a minor degree [13]. The positive results ap-plied to both obesity-specific psychosocial problems and eating behavior as a func-tion of general health perception and psychological well-being. However, the earlyimprovements had subsided to some extent at 1 and 2 years after surgery. Never-theless, long-term improvement in the surgically treated group is noticeable,with statistically significant differences in relation to the outset and to the valuesof the control groups. Most obvious was the influence on obesity-specific problems,eating behavior, and general health and depression. The effects on the health-re-lated quality of life are probably related to the degree of weight loss, i. e., greaterweight loss yields greater positive effects on quality of life, to the same degree inboth men and women.
272 6 Quality of Life
OP
SIP – A
SIP – RP
SIP – SI
CH
HAD
QL
Treatment effects after 4 years
Source: Section for Healthcare Research, Sahlgrenska University Hospital, 1998.
Trivial Small Moderate Great
Surgically treated, weight loss >25%
Surgically treated, weight loss <25%
Controls
Figure 6.2 Health-related quality of life andobesity.Treatment effects after 4 years in the two groupsof the SOS study (n=1088): surgicaland conventional treatment (controls).Those treated by surgery have been groupedaccording to the size of the weight loss at4 years. The effect have been expressed in™standardized response mean (SRM)calculated as change in mean from baselineto 4 years divided by the standard deviation
for the change:± trivial (0 to �0.2)± small (0.2 to �0.5)± moderate (0.5 to �0.8)± great (0.8+).Obesity-related psychosocial problems (OP)Function: gait, free-time recreation,social interaction (SIP-A; SIP-RP; SIP-SI)Current Health (CH)Depression (HAD)Quality of life, global rating (QL)
Sullivan reported quality-of-life data up to 4 years after surgery [28]. The positiveeffects demonstrated the same patterns as in 2-year followup. A high retention ofeffects on quality of life requires a high retention of weight loss (20±25 %, Figure6.2). Moderate weight loss, less than 10 %, did not cause a relapse to the originalweight in the major obesity-specific scales (e. g., OP, Figure 6.3). The results aresimilar in men and women. Continued, unchanged values concerning quality oflife were noted in the control groups. Improvements in psychosocial functionand well-being showed that patients with major weight loss approached the levelsof normal weight individuals. Even the high prevalence of suspected depressionprior to treatment was nearly normalized in the group with major (20±25 %)weight loss.
2736.3 Results
70
60
50
40
30
20
10
0
OP
Obesity-related psychosocial problems – OP
Baseline
Source: Section for Healthcare Research, Sahlgrenska University Hospital, 1998.
6 months 1 year 2 years 3 years 4 years
<10 kg
10–19.9 kg
20–29.9 kg
30+ kg
Controls
Figure 6.3 Obesity-related psychosocial prob-lems (OP scale).Treatment effects over time in the two groups ofthe SOS study (n=1088): surgical and conven-
tional treatment (controls). The effect in thosetreated by surgery is shown in relation to thesize of the weight loss at 4 years.
6.3.6Effects of Non-Surgical Treatment on Quality of Life
A 2-year followup of 60 moderately overweight women who were treated witheither vegetarian or non-vegetarian diets reported an average weight reduction of3.9 kg among those who complied with the vegetarian diet program [12]. Theothers increased in weight by 1.8 kg. The study documented health-related qualityof life and eating behavior prior to the study and after 3, 8, and 24 months(75 % followup rate at 2 years). The study shows that overweight women wholost weight generally experienced greater self-esteem and well-being during weightloss, but their mood afterward returned to, or became worse than, the level at theoutset due to difficulty in maintaining the diet and the lower weight. Functionalstatus also improved in conjunction with weight loss, and the women whocomplied with the study reported a significant improvement in physicalfunction after 2 years. Self-rated eating behavior prior to treatment correlatedwith later weight increase. This study demonstrates the importance that long-term followup of conventional dietary treatment effects has on health-related qual-ity of life.
Two large randomized multicenter trials addressed the measurement of qualityof life. One study focused on dietary treatment (comparative study for 1 year, nocontrols [21]). The second focused on pharmacotherapy (placebo-controlled, dou-ble-blind, orlistat study for 2 years) [23].
Both studies report significant effects on quality of life, but without thoroughreporting of data. Also, both studies measure quality of life by general andnutritional- and obesity-related measures, probably study-specific, but un-known outside of these studies. The quality-of-life effect in the orlistat study islimited to differences in satisfaction with the treatment attempt, weight loss,medication, and the total dieting program between placebo and high- and low-dose groups of patients receiving medication. These assessments comprise animportant part of the umbrella concept, Patient Reported Outcome (PRO),but do not belong to the conceptual model for quality-of-life measurement[5]. The second study reports p-values, statistical significance, for effects inall tested scales in the hypertension/dyslipidemia and type-2 diabetes diseasegroups. The study includes both overweight and obese people. The methodssection describes a procedure for calculating effect size and a selected thresholdat 0.3 points for the lowest meaningful clinical change for reporting results.Neither of these studies can be assessed based on the criteria for assessing qualityof life.
A randomized comparative study investigated the influence of weight loss onasthma in 38 patients with obesity and asthma [25]. The experimental groupcompleted a treatment program as a group, including VLCD (very low caloriediet), while the control group conducted a discussion program as a groupduring the same period. The primary outcome measures included a well-established health/quality-of-life measure used in pulmonary medicine to assessthe impact of disease as regards symptoms, activities, and social/psychological
274 6 Quality of Life
consequences [11]. After 1 year, the treatment group had improved more than thecontrol group in all respects. Weight loss averaged 11 % in the treatment group ver-sus 2 % weight gain in the control group.
Several smaller studies have used an obesity-specific IWQOL (Impact of Weighton Quality of Life Questionnaire) developed in the United States following inter-views with obese individuals [16]. Psychometric and clinical assessment and inclu-sion of instruments in the pharmacological testing resulted in a short form,IWQOL-Lite, with improved psychometric characteristics [17, 18].
Two studies are particularly noteworthy. The first concerns effects of moderateweight loss on quality of life, combining data from 4 randomized, double-blind,controlled multicenter trials of sibutramine versus placebo [24]. The study focusedon responsiveness in quality-of-life measures, i. e., whether it follows a dose-re-sponse pattern after 8 to 12 weeks, 24 to 28 weeks, and 1 year. Mainly at 24 to28 weeks, significant effects were achieved in several variables, e. g., physical func-tion, general health, and vitality. Regarding a total quality-of-life index, a minor ef-fect was reported in patients with weight loss of 5±10 %. At 1 year, the dose-re-sponse pattern was substantially weaker. The study, however, involves a shorttime frame, and concluded after 1 year.
The second study is a descriptive, 1-year followup of 141 women and 20 menusing a combined diet and medication program (combination phentermine-fenfluramine) to determine the effects on physical function, self-esteem, sexlife, public distress, and work [17, 18]. A significant correlation was found be-tween the degree of weight loss (approximately 18 %) and improvement in qualityof life. Approximately 14 % of the 1-year change in total points was explainedby weight change. The threshold value, based on the criteria for meaningfulchange, was approximately a 10-point difference. Hence, the greater the weightloss the greater the percentage of patients who passed this threshold. Inthe group with the least weight loss (� 10 %) 44 % were above the thresholdvalue, and in the group with the greatest weight loss (20 %) the rate was 76 %.This pattern was significant for physical function, sex life, and self-esteem, butnot for work and public distress. The study needs to be replicated in controlledtrials over a longer period, in larger groups, and with a higher percentage ofmen. Alternative methods for the least clinically meaningful difference shouldalso be tested.
2756.3 Results
6.4Appendix: Conclusions and Need for Research
6.4.1Quality of Life1) and Obesity: Population Studies
Obese people differ from overweight and normal weight people in the population.They report lower scores on function and well-being, more in a physical than in apsychological sense. The greatest differences concern physical function, generalhealth, and vitality.
Generally, the greater the obesity the lower is the quality of life, mainly in regardto physical aspects. Overweight individuals, however, differ only marginally fromnormal weight individuals.
In extremely obese individuals, both physical and psychological aspects are sub-stantially impaired, mainly physical function, role function ± physical causes, pain,general health, vitality, and social function.
The greater the comorbidity, the lower is the quality of life.Weight change (gain negative and loss positive) influences physical health more
than psychological health in women.
6.4.2Quality of Life and Obesity: Clinical Studies
Obese people differ from overweight and normal weight people in the populationwith greater margins than in corresponding comparisons of population samples.
Psychological well-being in severely obese patients is worse than that in the gen-eral public. Affective disorders are most common.
Psychosocial problems caused by obesity are common. Women are more affectedthan men.
Obese, especially severely obese, patients report lower function and well-beingcompared to many groups of chronically ill patients.
6.4.3Quality of Life after Surgery for Severe Obesity
Surgical treatment represents the only long-term, effective method for substantialand maintained weight loss and, subsequently, for effects on quality of life. Im-provements in quality of life can be assessed and related to weight loss. The greaterthe weight loss, the greater are the effects on quality of life in both men andwomen.
If weight loss is very substantial (20±25 %), psychosocial function and well-beingare nearly restored, i. e., to a level similar to that of the general public.
276 6 Quality of Life
1) ™Qualityof life as a measure in the field ofmedicine is synonymous with the concept of™health-relatedquality of life .
Also, with very substantial weight loss (20±25 %), the high prevalence figures forsuspected depression are nearly normalized.
6.4.4Quality of Life after Nonsurgical Treatment for Obesity
Short-term effects on quality of life (less than 1 year) have been documented withmoderate weight loss.
6.4.5Need for Further Research
Further research should document the following, insufficiently addressed, areas:Obese people in the population and obese patients who are physically inactive
report a lower quality of life. The causal relationship is, however, unclear. The im-pact of lifestyle factors on quality of life in obese people should be studied ingreater detail.
™Yo-yo dieting, i. e., numerous dieting attempts, is thought to have a negativeimpact on quality of life in overweight/obese men and women alike. However,the influence of yo-yo dieting on quality of life has been insufficiently assessed.
Some studies have shown that weight loss has promising effects on quality of lifein obese people with another specific chronic diagnosis, e. g., asthma, type 2 dia-betes, and hypertension. Further research is needed regarding quality of life ben-efits for obese people with comorbidities. This requires the use/development of di-agnosis-specific quality-of-life instruments (e. g., SGRQ for respiratory conditions)to cover disease-specific functional impairments and symptoms/problems.
2776.4 Appendix: Conclusions and Need for Research
278 6 Quality of Life
References
1. Barofsky I, Fontaine KR, Cheskin LJ.Pain in the obese: impact on health-related quality of life. Ann Behav Med1997;19:408-10.
2. Brown WJ, Dobson AJ, Mishra G.What is a healthy weight for middleaged women? Int J Obes 1998;22:520-8.
3. Brown WJ, Mishra G, Kenardy J, Dob-son A. Relationships between bodymass index and well-being in youngAustralian women. Int J Obes2000;24:1360-8.
4. Burns CM, Tijhuis MAR, Seidell JC.The relationship between quality of lifeand perceived body weight and dietinghistory in Dutch men and women. IntJ Obes 2001;25:1386-92.
5. Chassany O, Sagnier P, Marquis P,Fullerton S, Aaronson NK, for the Eu-ropean Regulatory Issues on Health-Related Quality of Life Assessment(ERIQA) Group. Patient-reported out-comes and regulatory issues: the ex-ample of health-related quality of life.DIA Journal 2002;36:209-38.
6. Doll HA, Petersen SEK, Stewart-BrownSL. Obesity and physical and emo-tional well-being: Associations betweenbody mass index, chronic illness, andthe physical and mental componentsof the SF-36 questionnaire. Obes Res2000;8:160-70.
7. Fine JT, Colditz GA, Coakley EH, Mo-seley G, Manson JAE, Willett WC, et al.A prospective study of weight changeand health-related quality of life inwomen. JAMA 1999;282:2136-42.
8. Fontaine KR, Cheskin LJ, Barofsky I.Health-related quality of life in obesepersons seeking treatment. J Fam Pract1996;43:265-70.
9. Fontaine KR, Bartlett SJ, Barofsky I.Health-related quality of life amongobese persons seeking and not cur-rently seeking treatment. Int J EatDisord 2000;27:101-5.
10. Han TS, Tijhuis MAR, Lean MEJ, Sei-dell JC. Quality of life in relation tooverweight and body fat distribution.Am J Public Health 1998;88:1814-20.
11. Jones PW, Quirk FH, Baveystock CM.The St George's Respiratory Question-naire. Respir Med 1991;85:25-35.
12. Karlsson J, Hallgren P, Kral J, LindroosAK, Sjöström L, Sullivan M. Predictorsand effects of long-term dieting onmental well-being and weight loss inobese women. Appetite 1994;23:15-26.
13. Karlsson J, Sjöström L, Sullivan M.Swedish obese subjects (SOS) ± an in-tervention study of obesity. Two-yearfollowup of health-related quality of life(HRQL) and eating behavior after gas-tric surgery for severe obesity. Int JObes 1998;22;113-26.
14. Karlsson J, Sjöström L, Sullivan M.Quality of life (HRQL) in obese seek-ing treatment compared to non-obesereference subjects. Qual Life Res2001;10:273.
15. Katz DA, McHorney CA, Atkinson RL.Impact of obesity on health-relatedquality of life in patients with chronicillness. J Gen Intern Med 2000;15:789-96.
16. Kolotkin RL, Head S, Hamilton M, TseC J. Assessing impact of weight onquality of life. Obes Res 1995;3:49-56.
17. Kolotkin RL, Crosby RD, Kosloski KD,Williams GR. Development of a briefmeasure to assess quality of life inobesity. Obes Res 2001;9:102-11.
279References
18. Kolotkin RL, Crosby RD, Williams GR,Hartley GG, Nicol S. The relationshipbetween health-related quality of lifeand weight loss. Obes Res 2001;9:564-71.
19. Larsson U, Karlsson J, Sullivan M.Impact of overweight and obesity onhealth-related quality of life ± a Swed-ish population study. Int J Obes2002;26:417-24.
20. Le Pen C, Levy E, Loos F, Banzet MN,Basdevant A. ™Specific scale comparedwith ™generic scale: a double mea-surement of the quality of life in aFrench community sample of obesesubjects. J Epidemiol CommunityHealth 1998;52:445-50.
21. Metz JA, Stern JS, Kris-Etherton P,Reusser ME, Morris CD, Hatton DC,et al. A randomized trial of improvedweight loss with a prepared meal planin overweight and obese patients. Im-pact on cardiovascular risk reduction.Arch Intern Med 2000;160:2150-8.
22. Richards MM, Adams TD, Hunt SC.Functional status and emotional well-being, dietary intake, and physical ac-tivity of severely obese subjects. J AmDiet Assoc 2000;100:67-75.
23. Rössner S, Sjöström L, Noack R,Meinders E, Nosedal G on behalf ofthe European Orlistat Obesity StudyGroup. Weight loss, weight mainte-nance, and improved cardiovascularrisk factors after 2 years treatment withorlistat for obesity. Obes Res 2000;8:49-61.
24. Samsa GP, Kolotkin RL, Williams GR,Nguyen MH, Mendel CM. Effect ofmoderate weight loss on health-relatedquality of life: an analysis of combineddata from 4 randomized trials of sibu-tramine vs placebo. Am J Manag Care2001;7:875-83.
25. Stenius-Aarniala B, Poussa T, Kvarn-ström J, Grönlund EL, Ylikahri M,Mustajoki P. Immediate and long termeffects of weight reduction in obesepeople with asthma: randomised con-trolled study. BMJ 2000;320:827-32.
26. Sullivan M, Sullivan L, Kral J. Qualityof life assessment in obesity: physical,psychological, and social function.Gastroenterol Clin North Am1987;16:433-42.
27. Sullivan M, Karlsson J, Sjöström L,Backman L, Bengtsson C, Bouchard C,et al. Swedish obese subjects (SOS) ±an intervention study of obesity. Base-line evaluation of health and psycho-social functioning in the first 1743subjects examined. Int J Obes1993;17:503-12.
28. Sullivan M, Karlsson J, Sjöström L, TaftC. Why quality-of-life measures shouldbe used in the treatment of patientswith obesity. In: P Björntorp (ed), In-ternational textbook of obesity, Chi-chester: Wiley, 2001;485-510.
29. Wadden TA, Sarwer DB, Womble LG,Foster GD, McGuckin BG, SchimmelA. Psychosocial aspects of obesity andobesity surgery. Surg Clin North Am2001;81:1001-24.
