Bariatric treatments for adult obesity - Institute of Health Economics

The investigators pointed out that the effects of weight loss on mortality rate cannot be evaluatedseparately within the two study groups, given the limits of the study’s statistical power. Therefore, itcannot be determined whether the favourable survival effect of bariatric surgery is explained byweight loss or by other beneficial effects of the surgical procedures.Findings from other SRs that assessed multiple treatment strategiesOne comprehensive systematic review/HTA, 2 published in 2004, assessed the evidence on the safetyand efficacy/effectiveness of various bariatric treatment strategies—including dietary therapy,exercise, behavioural therapy, pharmacotherapy, and surgery—in patients with a BMI of 28 kg/m 2or greater. A number of articles have been published on different outcomes from this review; theseare listed in the exclusion table in Appendix T.B. The results from the original review that assessed84 RCTs are briefly summarized below.Weight loss, risk factors/comorbiditiesDietary therapyLow-fat diets (which included 600 kcal/day deficit diets) were associated with the prevention of type2 diabetes and improved control of hypertension. These diets were associated with a weight loss ofapproximately 5 kilograms after 12 months and an improvement in risk factors, with weight losscontinuing for 3 years. Insufficient evidence was available to assess the putative benefits of lowcalorieor very-low-calorie diets.Adding physical exercise to dietary therapyThe addition of an exercise program to dietary therapy was associated with improved weight lossand risk factors for at least 1 year. Studies that combined low-fat diets and exercise, with or withoutbehavioural therapy, suggested improved control of hypertension and type 2 diabetes.Adding behavioural therapy to dietary therapyThe addition of a behavioural therapy program to dietary therapy was also associated with improvedweight loss for at least one year.Adding exercise and behavioural therapy to dietary therapyIt was unclear whether both exercise and behavioural therapy together further enhanced the effectof dietary therapy.Adding medications to dietary therapyUse of orlistat was associated with a weight loss of approximately 3 kilograms after 2 years, and withbeneficial changes in risk factors. Sibutramine was associated with a weight loss of 3 kilograms after18 months for people on a maintenance diet and with beneficial changes in risk factors except fordiastolic blood pressure.In addition to the RCTs on short-term outcomes, this review also included 37 observational studiesfor long-term outcomes.MortalityFor women with obesity-related comorbidities, intentional weight loss, irrespective of the amount ofweight lost, was associated with risk reduction of death, death from cardiovascular disease, cancer,Bariatric treatments for adult obesity 92