Outcomes of pharmacological and surgical treatment for obesity

The purpose of this article is to review the data from pharmacotherapeutic and surgical intervention studies for the management of obesity. Clinical outcomes assessed include weight changes over time and the effects of weight loss on blood pressure, serum lipid profiles and blood glucose control. Quality of life and economic data have been incorporated where available. Double-blind, randomised controlled trials were used preferentially over shorter term open studies. The literature evaluation was based on a Medline search of published data between January 1990 and January 1998. Obesity affects 65 million adults in the US. Estimates based on 1990 data suggest that obesity and comorbid illness contributed to $US46 billion in direct costs and $US23 billion in indirect costs in the US. Obesity is a chronic condition which requires long term management. The risk of developing cardiovascular disease, hypertension, type 2 (non-insulin-dependent) diabetes mellitus, osteoarthritis, Pickwickian syndrome and cancer is increased in the obese population, resulting in excess morbidity and mortality. There are no long term prospective studies that have demonstrated that weight reduction in obese patients improves survival. However, on the basis of epidemiological data using the prevalence of disease and associated body mass index, it is generally accepted that weight reduction of 5 to 10% in obese patients is associated with significant health benefits. Current treatment modalities include diet and behaviour modification, exercise and, where indicated, pharmacological intervention. Surgical intervention is reserved for the clinically severe obese patient [body mass index (BMI) > 40 kg/m2]. Many studies have demonstrated weight loss and improved metabolic fitness over 6 to 12 months. Few studies have been conducted over a longer period. Limited data are available regarding reduced morbidity and mortality, improved quality of life and functional or employment status and even fewer have incorporated any economic assessments of the impact of medical or surgical intervention. Although prospective data have demonstrated reduced morbidity following surgical intervention, only retrospective data have demonstrated reduced mortality. Studies of new drugs and interventions under development should demonstrate long term safety and efficacy in terms of sustained weight loss and subsequent weight maintenance. Future studies should incorporate assessment of patient perceived satisfaction with weight loss, health status and quality-of-life evaluations and pharmacoeconomic data to aid clinicians in the decision-making process in terms of weight management of their obese patients.