Abstract 6269: Weight Loss Pharmacotherapies: Are Treatment Effects Maintained between 6 and 12 Months?
Background: Orlistat, rimonabant, and sibutramine are the only three weight loss agents approved in North America for long-term use. Although these agents are effective at promoting weight loss and improving some cardiovascular risk factors, it is unclear if these treatment effects are maintained between 6 and 12 months.
Methods: We systematically reviewed the literature to identify double-blind, placebo-controlled randomized controlled trials (RCTs) examining the efficacy and safety of orlistat, rimonabant, and sibutramine. We limited our search to RCTs that examined the effect of clinically-used dosages of these agents (orlistat: 360 mg; rimonabant: 20 mg; sibutramine: 15 mg) on weight loss or cardiovascular risk factors at 6 and 12 months. Data were pooled using random effects models.
Results: We identified 34 RCTs, randomizing a total of 14,720 patients (orlistat: 23 RCTs, 8,806 patients; rimonabant: 4 RCTs, 4,105 subjects; sibutramine: 7 RCTs, 1,809 patients). All 3 pharmacotherapies were effective at promoting weight loss but had heterogeneous effects on other cardiovascular risk factors. Studies examining rimonabant only reported 12 months outcomes. Effects of orlistat and sibutramine were maintained between 6 and 12 months (Table⇓). We were unable to estimate the effects of sibutramine on LDL and HDL at 6 months as well as fasting glucose at 12 months due to insufficient data.
Conclusion: Orlistat, rimonabant, and sibutramine are more effective at promoting weight loss than placebo. However, sibutramine has neutral effects on LDL and deleterious effects on blood pressure. Treatment effects for orlistat and sibutramine were similar at 6 and 12 months, suggesting that the initial treatment effects of these agents are maintained long-term provided that patients continue therapy.