Obesity treatment in elderly outpatients: Predictors of efficacy and drop-out

Vol. 14: e56-e65, June-September 2009

e56

ORIGINALRESEARCH

PAPER

Key words:Elderly, weight loss, diet,physical activity.Correspondence to:Dr. Luca Buseto,Clinica Medica I,Policlinico Universitariodi Padova,Via Giustiniani 2,35128 Padova, Italy.E-mail: [email protected]: June 5, 2008Accepted: October 17, 2008

Obesity treatment in elderlyoutpatients: Predictors of efficacyand drop-out

INTRODUCTION

The prevalence of obesity in the elderlyis increasing. According to a national1999-2002 examination survey, the preva-lence of obesity, defined as a body massindex (BMI) ≥30 kg/m2, among Americanadults aged more than 60 years was 30.5%in men and 34.7% in women (1). Coupledwith the increase in the total number of

older persons in the population, theincreased percentage of the older popula-tion that is obese may cause a hugeincrease in the absolute number of obeseolder persons. Obesity causes seriousmedical complications and impairs qualityof life in the elderly as in adults. Moreover,in older persons, obesity can exacerbatethe age-related decline in physical functionand lead to frailty (2).

L. Busetto, M. Mazza, S. Salvalaio, F. De Stefano, M. Marangon, E. Calò,S. Sampietro, and G. Enzi

Unit for Medical and Surgical Therapy of Obesity, Department of Medical and Surgical Sciences, Universityof Padova, Padova, Italy

ABSTRACT. OBJECTIVE: Obesity is increasing in the elderly and it is associated with anincreased risk of medical complications, decline in physical function and disability. Very fewstudies specifically evaluated the outcome of obesity treatment in the aging patients. Aim ofthis work is therefore the evaluation of the efficacy of medical therapy in a group of obesepatients ≥65 years old. METHODS: The study has been performed on the clinical records ofobese outpatients treated at the medical branch of the Unit for Medical and Surgical Therapyof Obesity at the University of Padova. Patients were recruited from January 1st, 2001 to June30th, 2006 in order to have patients with at least one year of potential follow-up. In particulartwo groups were enrolled: 100 patients ≥65 years old and 200 patients <65 years old. Thebaseline characteristics, the prescriptions and the treatment outcome were compared.RESULTS: Mean age of the elderly patients was 69.1±3.7 years (range 65-80 years). We didnot find any significant difference between elderly and adult patients in the sex distribution(female patients 76% in the elderly group and 72% in the adult group; p=0.276) and in theseverity of overweight (body mass index: 37.8±6.0 kg/m2 in the elderly; 37.2±6.3 kg/m2 inadults; p=0.425). The elderly group was characterized by a higher incidence of comorbiditiesand a lower incidence of eating behavior disorders at baseline. No significant differences inthe dietary prescription were found, whereas physical activity was prescribed in 27/100elderly patients (27%) and in 97/200 (48%) adults patients (p<0.000). Weight loss was evaluat-ed by analyzing the percentage of patients reaching at least a 10% weight loss from baselineafter 12 months of treatment. In elderly patients still in active treatment after 12 months, only5/28 (18%) patients reached the specified goal, whereas in adult patients still in treatment,18/47 (38%) patients reached the goal (p<0.05). Lower age at baseline, female sex, and lowerbody mass index were found to be the only significant predictors of 10% weight loss in logis-tic regression. In our experience, drop-out rate after 12 months was similar in adults (77%)and in older patients (72%). In a multivariate Cox regression model, the risk of drop-out wasreduced by married or widowed status, the prescription of physical activity at baseline, andthe presence of type 2 diabetes. The risk of drop-out was increased by the presence ofosteoarthritis. Even after adjustments for these confounding variables, age did not play anysignificant role as drop-out predictor. CONCLUSION: Advanced age seems to be a predic-tor of poor response to treatment in obese outpatients treated by conventional medical thera-py. Drop-out rate was not significantly influenced by age.(Eating Weight Disord. 14: e56-e65, 2009). ©2009, Editrice Kurtis

© 2009, Editrice Kurtis

FOR PERSONAL USE ONLY

Obesity treatment in the elderly

e57Eating Weight Disord., Vol. 14: N. 2-3 - 2009

Despite these considerations, studies specifi-cally evaluating the outcome of obesity treat-ment in the older patients are very scarce in theliterature and the appropriate clinical approachto obesity in older persons is still controversial.Weight loss may result in a decrease in both fatmass and lean body mass and therefore it ispossible that weight loss in obese older personscould worsen the age-related loss of musclemass, increase sarcopenia, and cause disability(2). On the other hand, according to a recenttechnical review and position statement on obe-sity in older adults of the American Society forNutrition and the North American Associationfor the Study of Obesity, weight-loss therapythat minimizes muscle and bone losses may berecommended for older persons who are obeseand who have functional impairments or meta-bolic complications that can benefit fromweight loss (2). However, the efficacy in olderobese patients of the conventional therapeuticapproaches normally used in adults has beenpoorly studied in the clinical setting. Someintervention trials with therapeutic lifestylemodifications specifically conducted in elderlyobese patients seem to suggest that lifestyleintervention may produce a significant weightloss in elderly people as in adult patients (3-5),but none of these studies included a direct com-parison between patients of different ages. Inthis study we provided data about the efficacyof medical therapy in a group of obese patients≥65 years old. The outcome of the group ofpatients ≥65 years old was compared with theoutcome of a large group of patients <65 yearsold treated with an identical therapeutic pro-gram. Predictors of efficacy and adherence tothe therapy were also investigated.

METHODS

The present study was designed as a retro-spective survey, based on subjects attendingthe medical outpatient service of the Unit forMedical and Surgical Therapy of Obesity of theUniversity of Padova. Patients were randomlyrecruited from the whole sample of obesepatients attending the service since January2001 to June 2006, in order to have a minimumpotential follow-up of one year to the indexdate of June 30, 2007. A total of 100 patients≥65 years old and 200 obese outpatients <65years old were selected. The only exclusion cri-teria included: BMI <25 kg/m2, pregnancy,endocrine diseases, cancer and severe mentalillness. Patients receiving an indication tobariatric surgery and shifted to the surgicaloutpatient service of our institution were also

excluded. Giving the restrospective nature ofthe study no informed consent was obtainedfrom the patients.All patients underwent at baseline a complete

clinical examination, which included a generalquestionnaire, constructed in our center, con-cerning sociodemographic and lifestyle data,family and personal obesity history, previousanti-obesity treatments; obesity-related comor-bidities (hypertension, type 2 diabetes, dyslipi-demia, hyperuricemia or gout, cardiovasculardiseases, sleep apnea, osteoarthritis anddepression) and eating behavior disorders(binge eating disorder, sweet eating, grazingand night eating). Education attainment wasmeasured in years of schooling. Civil statuswas defined as single, married or widowed.The level of physical activity was assessed withquestions on hours of mild, moderate, high andvigorous activity undertaken each week andscored from 1, which corresponds to sedentarylife, to 5, which corresponds to vigorous physi-cal activity. Cigarette smoking was defined ascurrent, past or never. Alcohol intake was clas-sified as abstinence, moderate alcohol intake(corresponding to 1-250 ml of wine per day orequivalent), medium (251-500 ml of wine perday or equivalent) or high (>500 ml of wine perday or equivalent). The diagnosis of binge eat-ing disorder was based on the proposed diag-nostic criteria of the Diagnostic and StatisticalManual of Mental Disorders, fourth edition(DSM-IV) (6). Sweet eating was diagnosedwhen the patient craved simple carbohydrates,and carbohydrate craving could be continuous-ly present or triggered by emotional (anxiety,stress) or physiological (premenstrual phase)situations (7). Grazing was diagnosed when thepatient ate small quantities of foods repetitivelybetween meals, typically triggered by inactivityand/or loneliness (7). Night eating syndromewas defined according to the diagnostic crite-ria proposed by Stunkard et al. (8).At baseline all patients received a complete

clinical examination which included anthropo-metric measurements. All anthropometric mea-surements were performed with the subjectswearing light clothes without shoes. Height wasmeasured to the nearest 0.01 m using a wall-mounted stadiometer. Body weight was deter-mined to the nearest 0.05 kg using a calibratedbalance beam scale. BMI was calculated asweight (kg) divided by the height-squared (m2).

Treatment programTreatment program in our centre was based

on a combination of mild hypocaloric diet, mod-erate physical activity, and behavioral reinforce-ment, in agreement with the Clinical Guidelines



L. Busetto, M. Mazza, S. Salvalaio, et al.

e58 Eating Weight Disord., Vol. 14: N. 2-3 - 2009

on the Identification, Evaluation, and Treatmentof Overweight and Obesity in Adults of theNational Institutes of Health (9). The basis of theprogram consisted in a first clinical evaluationfollowed by individual control visits, plannedevery 8 weeks at least. Follow-up visits werescheduled time by time, but no routine recallsystem for the patients with missed visits wasactive. All visits were made by a physiciantrained on obesity treatment. The costs of base-line evaluation and follow-up visits were totallyor partially paid by the patient to the institutionaccording to the prices and regulationsimposed by the National Italian Health Service.No direct payments to the physicians were per-mitted. A general treatment plan was formulat-ed at the baseline evaluation and regularly re-examined during follow-up. On the follow-upvisits, the physician assisted the patient in themonitoring of weight, and addressed certainthemes such as self-monitoring, reinforcement,nutritional education and beneficial effects ofphysical activity, in order to promote behav-ioural modifications and dietary changes.The daily energy content of the mild hypo-

caloric diet was individually calculated in orderto obtain a daily energy deficit of 400-600kcal/day in respect to the estimated total dailyenergy expenditure of the patient. Total dailyenergy expenditure was estimated from the basalmetabolic rate calculated with the World HealthOrganization (WHO) formula with correction forhabitual physical activity level (10). No diets withdaily energy content lower than 1000 kcal/daywere prescribed. The composition of the diet wasarranged to a target of 15–20% of the energyintake from proteins, 25–30% from lipids and50–55% from carbohydrates. A high intake ofcomplex carbohydrates and fiber was recom-mended and a particular emphasis was given tothe reduction of lipids, alcohol and sweet drinks.Patients were strongly encouraged to adhere tothree main meals a day and two snacks largelybased on fresh fruit, but the distribution andcomposition of meals may be individualizedaccording to patient’s preferences and needs.The minimum physical activity level targeted

for patients with a baseline sedentary lifestylewas represented by at least 3 hours per week ofphysical activity (9). Moderate intensity physi-cal activities were privileged, but the type ofphysical activity may be adapted to patient’spreferences and attitudes. Simple schemes ofprogressive training were provided to patientswith baseline sedentary lifestyles, but not indi-vidualized training program or formal collabo-ration with professional trainers was active.Anti-obesity drugs may be added to the ther-

apeutic program since baseline evaluation or

during follow-up according to the treatingphysician’s judgment in patients with BMI >30kg/m2, or in patients with BMI >27 kg/m2 andsignificant obesity-related comorbidities. Onlytwo drugs with a labeled indication for obesitytreatment were available in Italy during thestudy period: sibutramine and orlistat.In agreement with international guidelines

(9), a primary goal of a moderate weight loss,corresponding to 10% of the baseline bodyweight, was set and discussed with thepatients. In case of attainment of the primarygoal, further therapeutic objectives may bestipulated according to individual clinical con-ditions, but a particular emphasis to weightloss maintenance was given.

Statistical analysisStatistical analysis was performed by using

the SSPS statistical package, version 15.0 (SSPSInc., Chicago, IL). Frequencies, mean valuesand standard deviations were used to describethe baseline characteristics of the elderly andthe adult group at baseline. Differencesbetween the two groups were evaluated byunpaired Student’s t-test for numerical vari-ables and Chi-square test for categorical vari-ables. The efficacy of weight loss therapy wasevaluated by calculating in each study groupthe overall weight loss and the percentage ofpatients reaching the weight loss goal of atleast 10% of baseline body weight after 12months of treatment. These two analyses wereconducted both in completers and according toan intention-to-treat (ITT) model with the lastobservation carried forward (LOCF). Predictorsof efficacy were tested by stepwise logisticregression analysis. Adherence to therapy wasevaluated up to the third year of follow-up andthe difference in survival in active treatmentbetween the elderly and the adult group wasassessed with the log-rank test for comparisonof Kaplan-Meier survival curves. Predictors ofdrop-out were investigated by multivariate(Cox) regression analysis in the sample as awhole. In all statistical analysis, a p-value lessthan 0.05 was considered to be significant.

RESULTS

Baseline evaluationThe baseline characteristics of 100 obese out-

patients ≥65 years old and 200 obese outpa-tients <65 years old attending the medicalbranch of the Unit for Medical and SurgicalTherapy of Obesity of the University of Padovaare reported in Table 1. The two groups had asimilar sex distribution, with women represent-





TABLE 1Clinical characteristics at the baseline evaluation in 100 patients ≥65years old and in 200 patients <65 years old selected out of the popu-lation of obese outpatients attending the medical branch of the Unit forMedical and Surgical Therapy of Obesity, University of Padova, Italy.

ing about three quarters of the study popula-tion. Mean age in elderly patients was 69.1±3.7years, with a range from 65 to 80 years. In par-ticular, 68 patients were 65-70 years old, 26patients were 71-75 years old, and 6 patientswere 76-80 years old at baseline. In addition tothe obvious difference in the age at baseline,elderly patients had significantly higher age atthe onset of obesity and duration of obesitythan adult patients.No significant differences in baseline BMI

were observed between elderly and adultpatients in our study (Table 1). Despite a similardegree of obesity, patients ≥65 years old weremore significantly affected by obesity-related

comorbidities. In particular, we observed ahigher prevalence of hypertension, type 2 dia-betes, dyslipidemia, hyperuricemia, cardiovas-cular diseases and osteoarthritis in the oldergroup (Table 1). On the contrary the prevalenceof most of the eating behavior disorders (bingeeating, sweet eating and grazing) was lower inthe elderly than in the adult patients. We did notobserve significant differences between the twogroups in the prevalence of depression andnight eating syndrome (Table 1). The higherprevalence of metabolic, cardiovascular andorthopedic comorbidities observed in elderlypatients translated in a more frequent use ofdrugs: the mean number of drugs used at base-line was 3.7±2.6 (range 0-12) in the elderlypatients and 1.6±1.9 (range 0-10) in the adultpatients (p<0.001). In particular, a more frequentuse of anti-hypertensive drugs and statins wasobserved in the elderly group (data not shown).Very few patients in both groups were alreadyin treatment with anti-obesity drugs at baselineevaluation: only one patient in the elderly groupand one patient in the adult group were in treat-ment with orlistat, none was taking sibutramine.Very few patients in both groups reported anacceptable level of physical activity, with a lowerprevalence in the elderly group (Table 1).The majority of both the elderly and the adult

patients reported previous attempts of weight-control therapy at baseline (Table 1). Previousweight loss treatment with energy restrictionwas reported by 66/100 (66%) patients in theelderly group and by 158/200 (79%) patients inthe adult group (p=0.003). Behavioral therapywas clearly under-used in both groups, with noelderly patient and only four adult patientsreporting previous behavioral treatments. Final-ly, 16/100 (16%) patients in the elderly group and43/200 (21%) patients in the adult group reportedprevious use of anti-obesity drugs. However,only few of the patients reporting previous use ofanti-obesity drugs referred previous use of drugscurrently indicated for obesity treatment in Italy[6/43 (14%) patients reporting previous pharma-cologic treatment with orlistat and 3/43 (7%)with sibutramine in the adult group; 2/16 (12%)patients reporting previous pharmacologic treat-ment with orlistat and 1/16 (6%) with sibu-tramine in the elderly group]. Most of thepatients in both groups reporting previous use ofanti-obesity drugs had been previously treatedwith multi-ingredients formulations of unknowncomposition or with short courses of ampheta-mines or amphetamines-like drugs.

Treatment outcomeAfter the baseline evaluation, all patients

received a moderate energy deficit diet, with no

≥65 years old <65 years old

Demographic characteristicsFemale sex, % 76/100 (76%) 144/200 (72%)Age at baseline, yr 69.1±3.7 (65-80) 43.2±12.7 (16-64)***

Obesity historyObesity family history, % 43/100 (43%) 130/200 (65%)***Age at the onset of obesity, yr 39.4±15.7 (6-77) 24.5±11.3 (3-60)***Duration of obesity, yr 29.6±15.0 (1-65) 18.4±12.2 (1-49)***Previous dietary treatment, % 66/100 (66%) 158/200 (79%)**Previous behavioral treatment, % 0/100 (0%) 4/200 (2%)Previous use of anti-obesity drugs, % 16/100 (16%) 43/200 (21%)

AnthropometryBody weight at baseline, kg 98.7±17.8 102.1±19.4

(56.5-167.0) (65.0-160.0)BMI at baseline, kg/m2 37.8±6.0 37.2±6.3

(25.5-54.2) (25.2-57.8)

ComorbiditiesHypertension, % 78/100 (78%) 83/200 (41%)***Type 2 diabetes, % 21/100 (21%) 25/200 (12%)*Dyslipidemia, % 49/100 (49%) 44/200 (22%)***Hyperuricemia/Gout, % 12/100 (12%) 8/200 (4%)*Cardiovascular diseases, % 15/100 (15%) 9/200 (4%)**Sleep apnea, % 43/100 (43%) 92/200 (46%)Osteoarthritis, % 73/100 (73%) 101/200 (50%)***Depression, % 26/100 (26%) 56/200 (28%)

Eating behavior disorderBinge eating disorder, % 5/100 (5%) 26/200 (13%)*Sweet eating, % 13/100 (13%) 53/200 (26%)***Grazing, % 14/100 (14%) 57/200 (28)%***Night eating, % 4/100 (4%) 4/200 (2%)

LifestylePrevious or current smokers, % 35/100 (35%) 82/200 (41%)High alcohol intake, % 8/100 (8%) 15/200 (7%)Moderate to high physical activity, % 2/100 (2%) 32/200 (16%)***

Values are means±standard deviation (range) for the numerical variables and per-centage for the categorical variables. High alcohol intake was defined as an intake ofmore than 250 ml of wine per day or equivalent. Moderate to high physical activitywas defined as at least 3 hours/week of brisk walking or equivalent. Unpaired Stu-dent’s t-test for numerical variables and Chi-square test for categorical variables wereperformed: *p<0.05; **p<0.01; ***p<0.001.





significant differences in prescribed daily ener-gy intake between elderly and adult patients(1334.7±166.0 kcal/day vs 1376.3±188.3 kcal/day;p=0.074). Moderate intensity daily physicalactivity was explicitly prescribed to 27/100elderly patients (27%) and to 97/200 (48%)adults patients, with a statistically significantlydifference in favor of the adult group (p<0.000).Finally, 12/100 (12%) elderly patients and 29/200(14%) adult patients received a prescription foran anti-obesity drug (orlistat or sibutramine),without significant differences between the twogroups (p=0.479). However, a clear differencewas observed in the type of anti-obesity drugmost frequently used: orlistat was prescribed in6/200 (3%) adults and in 10/100 (10%) elderlypatients (p=0.028), while sibutramine was pre-scribed in 23/200 (11%) adults and only in 2/100(2%) elderly patients (p=0.002). This differencein prescription was largely maintained duringfollow-up (data not shown).Weight loss in the first 3 years of follow-up in

elderly and adults patients, expressed as per-centage of baseline body weight, is representedin Figure 1. In completers (Fig. 1A), weight losswas slightly, but not significantly lower in theelderly group than in the adult group in thefirst year of treatment (weight loss at 6 months:5.7±5.5 vs 6.4±6.7%, p=0.560; weight loss at 12months: 6.2±6.9 vs 8.6±8.9%, p=0.228). After-ward, the weight loss curves of the two groupswere superimposable, but the significance ofthe results was reduced by the very low num-ber of patients still in active treatment after thefirst year of follow-up. In the ITT analysis con-ducted with the LOCF model (Fig. 1B), no sta-tistically significant differences between elderlyand adults patients were found. The efficacy ofweight loss therapy was also evaluated in a cat-egorical way, by calculating in each studygroup the percentage of patients reaching theweight loss goal of at least 10% of baselinebody weight after 12 months of treatment. Inelderly patients still in active treatment after 12months, only 5/28 (18%) had a weight loss≥10%. In adult patients still in treatment, 18/47(38%) had a weight loss of ≥10%. The differ-ence between the two groups resulted statisti-cally significant with a better result in adultpatients (p<0.05). When this efficacy analysiswas repeated according to an ITT principle, the≥10% weight loss goal after 12 months of treat-ment resulted to be achieved in 7/100 (7.0%)elderly patients and in 23/200 (11.5%) adultpatients (p=0.221).Predictors of efficacy were investigated by

stepwise logistic regression models withweight loss ≥10% of the baseline body weightafter 12 months of active treatment as the

dependent variable. In a first model the follow-ing independent variables were tested: gender,age at baseline, age at the onset of obesity,duration of obesity, BMI at baseline, educationlevel, civil status, physical activity level, alcoholintake, smoking, obesity family history, comor-bidities (hypertension, type 2 diabetes, dyslipi-demia, hyperuricemia/gout, cardiovascular dis-eases, sleep apnea, osteoarthritis, depression),and eating behavior disorders (binge eatingdisorder, sweet eating, grazing, night eating).In this model, only younger age at baseline,female sex and low BMI at baseline were found

100 62 44 33 28 16 14 8 7200 115 75 56 47 27 17 13 8

N: elderlyadults

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FIGURE 1Weight loss expressed as percentage of baseline body weight in 100patients ≥65 years old (closed symbols) and in 200 patients <65years old (open symbols) attending the medical branch of the Unitfor Medical and Surgical Therapy of Obesity, University of Padova,Italy. Weight loss was reported both for patients still in active treat-ment at each follow-up visit (panel A) and according to an intent-to-treat analysis model with the last observation carried forward inmissing patients (panel B). Numbers of patients still in active treat-ment at each follow-up visit are reported.





to be significant predictors of success (Table 2).In a second model, the following independentvariables related to treatment prescriptionwere added to the variables already tested inmodel 1: prescribed daily energy intake, pre-scription of physical activity, prescription oforlistat or sibutramine. The introduction of thissecond group of variables did not significantlymodify the results of the stepwise logisticregression analysis (Table 2). The total variabili-ty of the dependent variable explained by themodels was 39.4% for the first model and39.2% for the second model.Adherence to therapy was very low both in

elderly and adult patients. Total rate of drop-out after 12 months was 77% in the adult groupand 72% in the elderly group (p=0.210). Kaplan-Meier estimates of survival in active treatmentwere calculated up to the third year of follow-up and the difference in survival between theelderly and the adult group was assessed withthe log-rank test for comparison of Kaplan-Meier survival curves (Fig. 2): survival rate wasnot significantly different between the twogroups (p=0.522). Predictors of drop-out in thewhole sample were investigated by multivariateCox regression analysis. Gender, age at base-line, age at the onset of obesity, duration ofobesity, BMI at baseline, education level, civilstatus, physical activity level, alcohol intake,smoking, obesity family history, comorbidities,eating behavior disorders, prescribed dailyenergy intake, prescription of physical activityand prescription of orlistat or sibutramine

were entered in the analysis as possible predic-tors of drop-out. Independent determinants ofdrop-out according to this model are shown inTable 3: married or widowed civil status, thepresence of type 2 diabetes and the prescrip-tion of physical activity at baseline were foundto be protective factors against drop-out risk,whereas the presence of osteoarthritis wasfound to increase drop-out rate. Age was notfound to be an independent determinant ofdrop-out also in multivariate adjusted analysis.

DISCUSSION

In this study, we analyzed the response andthe adherence to therapy of an adequate groupof elderly obese patients treated with a lifestylemodification program, eventually associatedwith pharmacologic therapy, in the non-experi-mental setting of the usual outpatient clinicalactivity of an Italian obesity centre. The out-come of the group of patients ≥65 years old wascompared with the outcome of a large group ofpatients <65 years old. At baseline, elderlypatients were characterized by a lower level ofspontaneous physical activity, by a higherprevalence of comorbidities and by a lowerincidence of eating behaviour disorders. In oursetting, despite the use of exactly the sametreatment protocol in elderly and in adult sub-jects, patients >65 years old received less fre-quently a detailed prescription for physicalactivity. The primary goal of a weight loss cor-

β coefficient p

Model 1Age at baseline -0.107 0.009Female sex 3.148 0.010BMI at baseline -0.147 0.040

Model 2Age at baseline -0.106 0.009Female sex 3.101 0.011BMI at baseline -0.146 0.042

In Model 1 the following independent variables were tested: gender, age at base-line, age at the onset of obesity, duration of obesity, BMI at baseline, educationlevel, civil status, physical activity level, alcohol intake, smoking, obesity familyhistory, comorbidities (hypertension, type 2 diabetes, dyslipidemia, hyper-uricemia/gout, cardiovascular diseases, sleep apnea, osteoarthritis, depression),eating behavior disorders (binge eating disorder, sweet eating, grazing, nighteating). In Model 2 the following independent variables related to treatment pre-scription were added to the variables already tested in model 1: prescribed dailyenergy intake, prescription of physical activity, prescription of orlistat or sibu-tramine. BMI: body mass index.

TABLE 2Determinants of success in stepwise multiple regression analysis. Suc-cess was defined as a weight loss ≥10% of the baseline body weightafter 12 months of active treatment.

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FIGURE 2Kaplan-Meier estimates of survival in active treatment in 100 patientsaged ≥65 years (dotted line) and in 200 patients aged <65 years(solid line) attending the medical branch of the Unit for Medical andSurgical Therapy of Obesity, University of Padova, Italy.





responding to 10% of the baseline body weightwas reached in significantly fewer patients inthe elderly than in the adult group, andadvanced age was found to be an importantindependent predictor of a reduced therapeuticresponse, also after adjustment for other possi-ble confounding factors. The drop out rate wasvery high in both groups, but adherence totherapy was not significantly affected bypatients age.Our study had several important method-

ological limitations that may significantly affectthe reliability of our results. The first limit wasinherent to the design of the study, that wasnot a prospective trial, but a retrospectiveanalysis of outpatient data collected duringroutine clinical practice. Retrospective recruit-ment exposed to possible bias in the selectionof patients. We tried to reduce this possibilityby selecting patients in a random order fromour clinical database, without the use of strictinclusion or exclusion criteria, but possibleuncontrolled selection bias may well haveoccurred. On the other hand, using a retro-spective design for the study, we may affirmthat our data could be considered as a realdescription of our current clinical practice andtherefore may be more useful than experimen-tal data for the identification of our limits andthe suggestion of appropriate modifications tothe therapeutic protocol in elderly obesepatients. A second limit, probably again inher-ent to the fact that our study is an on-field clini-cal study and not a prospective clinical trial,was represented by the few data collected onthe evolution of comorbidities during follow-up. This is an important limitation because theevaluation of obesity-related comorbiditiescould be an important element in the evaluation

of treatment outcomes, in particular in theelderly. Data on health-related quality of lifeand functional dependence at baseline and dur-ing follow-up were also lacking. Finally, the useof simple questionnaires and not formal testingfor the diagnosis of eating behavior disordersmay cause an underestimation of their preva-lence in the sample. However, the lower preva-lence of eating behavior disorders found in theelderly group of this study was in agreementwith the age-related decline in the prevalenceof binge eating disorder described in popula-tion studies (11).Despite all these important limitations, our

study could give interesting clinical informationbecause it represents one of the few studies onobesity treatment in which a direct comparisonbetween elderly and adult patients was per-formed. Some intervention trials with therapeu-tic lifestyle modifications have been specificallyconducted in elderly obese patients. In the TrialOf Nonpharmacologic interventions in theElderly (TONE), 585 obese elderly patients withhigh blood pressure were randomized to alifestyle modification program targeted toweight loss, to a dietetic program focused onsodium intake, to a combination of both pro-grams, or to the usual antihypertensive therapy.In the lifestyle modification arm, mean weightloss was 3.5-4.5 kg, significantly greater than inthe other groups (3). In the Arthritis, Diet, andActivity Promotion Trial (ADAPT), 316 over-weight or obese patients aged over 65 yearsand affected by knee osteoarthritis were ran-domized to usual lifestyle recommendations(control group), to a diet program, to a physicalactivity program, or to a combination of dietand physical activity. A significant weight losswas observed after 18 months in all groups(5.7% of baseline body weight in the diet plusphysical activity group, 4.9% in the diet group,3.7% in the physical activity group, and 1.2% inthe control group) (4). Finally, Villareal et al.randomized a little group of 27 frail elderlypatients to a behavioral therapy program tar-geted to weight loss and physical activity or to acontrol group. The weight loss in the activetreatment arm was 8.4% of baseline bodyweight, while there was no significant weightloss in the control group. The treatment pro-gram improved also the physical performanceand the muscular strength of the patients (5). Allthese results seem to suggest that lifestyle inter-vention may produce a significant weight lossin elderly people as in adult patients (2), butnone of these studies included a direct compari-son between patients of different ages. In ourstudy, the 6.2% weight loss obtained in the firstyear of treatment in elderly patients was equiva-

ββ coefficient p

Civil status: married -1.173 0.031

Civil status: widowed -1.400 0.031

Osteoarthritis at baseline 0.760 0.010

Type 2 diabetes at baseline -0.826 0.038

Prescription of physical activity -0.606 0.020

The following independent variables were entered in the analysis as possible pre-dictors of drop-out: gender, age at baseline, age at the onset of obesity, durationof obesity, body mass index at baseline, education level, civil status, physicalactivity level, alcohol intake, smoking, obesity family history, comorbidities (hyper-tension, type 2 diabetes, dyslipidemia, hyperuricemia/gout, cardiovascular dis-eases, sleep apnea, osteoarthritis, depression), eating behavior disorders (bingeeating disorder, sweet eating, grazing, night eating), prescribed daily energyintake, prescription of physical activity, prescription of orlistat or sibutramine.

TABLE 3Determinants of drop-out in multivariate Cox regression analysis.





lent to or even higher than the body weightreductions found in the above mentionedpapers (3-5), but it remained a bit lower thanthe weight loss observed in adult patients. Thepercentage of completer elderly patients thatreached the primary goal of a weight loss corre-sponding to 10% of the baseline body weight atthe end of the first year of treatment (18%) wasapproximately half of the percentage found inthe younger group (38%). The reducedresponse to therapy found in elderly patients inour study was in contrast with the results of ananalysis performed in patients of different agesparticipating in the treatment arm of the Dia-betes Prevention Program (DPP) (12). In theDPP, 60% of patients >65 years old, but only43% of patients <45 years old, reached the goalof 7% weight loss after 24 weeks of intensivelifestyle modifications (12). On the other hand,several studies performed with different thera-peutic techniques seem to confirm a higherresistance to weight loss in elderly patients. In amulticentric study comparing the outcome of216 morbid obese patients >60 years old treatedwith laparoscopic gastric banding in 26 Italiansurgical centers with the outcome of 5074 adultpatients treated with the same surgical tech-nique in the same centers, the weight loss in theelderly group was approximately half of theweight loss observed in adults (13). A lowerweight loss in elderly patients was also foundafter gastric by pass (14).Several age-related factors may explain a

reduced responsivity to weight loss therapy inelderly obese patients. Studies analyzing thepredictive factors for a successful outcome inpatients treated with gastric banding suggestedthat age and other age-related factors, likeinsulin resistance, low physical activity leveland worse health status, can all play a signifi-cant role in reducing weight loss after the sur-gical procedure (7, 15). In our study, elderlypatients had a higher prevalence of metabolicdiseases related to insulin resistance, had a lowphysical activity level at baseline, and weremore affected by chronic diseases. However,the results of multivariate analysis suggestedthat age remains a negative predictive factor ofweight loss also after adjustment for all thesefactors, suggesting that age itself, irrespectiveof coexisting comorbidities, could play themajor predictive role, maybe in relation to theknown age-related changes in body composi-tion and resting energy expenditure.Apart from patient-related factors, the

reduced therapeutic response observed inelderly patients in our study may be also relat-ed to treatment-related factors. The daily ener-gy content of the diet prescribed at baseline did

not result to be significantly different in elderlyand in adult patients. Considering that thedietetic prescription was set with the use of theWHO/Food and Agriculture organization(FAO) formula, that calculates a lower basalmetabolic rate in people >65 years old, and thatthe correction for the physical activity levelshould be lower in the more sedentary elderlygroup, a lower caloric prescription should havebeen expected in elderly patients. The absenceof a significant difference in dietary prescrip-tion between the two groups could be causedby a conservative attitude of attending physi-cians, driven by the awareness of the possiblenegative effects of a low calorie diet on musclemass, sarcopenia and disability (2). However,the decision to apply a more conservative levelof caloric restriction in elderly subjects mayhave reduced the efficacy of the diet in thisgroup of patients. Physical activity was pre-scribed less frequently in the elderly group(27%) that in the adult group (48%) in ourstudy. Regular physical exercise may be notessential for weight loss, but it is critical forweight maintenance (9) and it is even moreimportant in the elderly for the prevention ofmuscle mass loss during weight reduction (2,12). The under-prescription of physical activityin the elderly patients by the attending physi-cians in our study may be driven by a perceivedgreater difficulty in performing exercise inolder subjects, related both to the low level ofbaseline spontaneous physical activity and tothe presence of respiratory, cardiovascular andorthopaedic comorbidities. Finally, also theprescription of anti-obesity drugs was signifi-cantly different in the two groups of patients,with a prevalent use of orlistat in elderlypatients and sibutramine in adults. The lowerutilization of sibutramine in older patients maybe explained by the higher prevalence in elder-ly patients of potential cardiovascular con-traindications to this drug and possibly by thelower prevalence of eating behavior distur-bances that may trigger the use of an anorecticdrug (2). The Sibutramine Cardiovascular OUT-comes (SCOUT) trial is now treating subjectsmost of whom have conditions that are explicit-ly contraindicated for sibutramine therapyunder the current label (coronary artery dis-ease, peripheral arterial occlusive disease orstroke). Preliminary data from the 6-week sin-gle-blind period of the SCOUT trial indicatethat weight management with the addition ofsibutramine is well tolerated even in high-risksubjects with cardiovascular disease (16).Accrual of more data about sibutramine safetyin high-risk subjects may promote a wider useof this drug also in the elderly. Overall, it is dif-





ficult to quantify the role of these treatment-related differences in explaining the reducedefficacy of weight loss therapy in our elderlypatients. However, the results of multivariateregression analysis did not seem to suggest animportant independent role for these factors, inaddition to that played by age and other bio-logical factors (sex and BMI levels).In our study a very high prevalence of drop-

outs was found. Drop-out rate was >50% after6 months of treatment and 75% after 12months, thus confirming the 77.3% drop-outrate after 12 months previously found by ourgroup in another subset of patients (17). Simi-lar drop-out rates have recently been reportedby other Italian groups. Cresci et al. reported adrop-out rate of 78.9% after 8 months of treat-ment in 57 patients assigned to an individualbehavior therapy program (18). Minniti et al.had a drop-out rate of 54.2% after 6 months oftreatment in 72 patients individually treatedwith cognitive behavioral therapy (19). Drop-out rate was relatively lower, but still elevated,in randomized trials with anti-obesity drugs. Inthe Sibutramine Trial of Obesity Reduction andMaintenance (STORM), the drop-out rate at 12months was 42% in the treated group and 50%in the placebo group (20). In the XENical in theprevention of Diabetes in Obese Subjects(XENDOS) study, the drop-out rate at thefourth year of follow-up was 48% in the treat-ed group and 66% in the placebo group (21).Finally, in the Rimonabant in Obesity-NorthAmerica (RIO-North America) study, the drop-out rate at 12 months was 45% in the treatedgroup and 49% in the placebo group (22). Analyzing the effects of age on adherence to

therapy, we did not find significant differencesin drop-out rate at 12 months between elderly(77%) and adult (72%) patients participating inour study and age was not an independent pre-dictor of drop-out in multivariate analysis. Inour study, the drop-out rate was more influ-enced by social factors (single against marriedor widowed civil status) and comorbidity status(presence of osteoarthritis and absence of dia-betes) than by age. These results confirm previ-ous observations made by our group in a dif-ferent set of patients, in which full-timeemployment, absence of depressive symptomsand presence of comorbidity, but not age atbaseline, were independent predictors of drop-out in outpatient obese subjects (17). However,the mechanisms by which these factors causedrop-out in our patients remained to be eluci-dated, since we did not collect any data aboutpersonal reasons for drop-out directly frompatients. Other works previously investigatedthe role of age on drop-out rate in outpatient

overweight and obese subjects and found con-trasting results, with some studies showing noage-related effects (23) and other studies sug-gesting a protective role of age against drop-out (19, 24-26). Differences in the age composi-tion of the patients and in the correction forother possible confounding variables couldprobably explain these discrepancies. In conclusion, our results suggest that weight

loss therapy may be even more difficult in over-weight and obese elderly patients than inyounger patients. Further studies are needed inorder to determine if an adaptation of the ther-apeutic protocol to the peculiar characteristicsand needs of the aged obese patients may beuseful in improving our success rates. In partic-ular, the usefulness of physical activity proto-cols specifically developed for elderly subjectsand the safety of pharmacologic therapy inhigh-risk older patients need to be investigated.

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Obesity treatment in elderly outpatients: Predictors of efficacy and drop-out