Long-term persistence with orlistat and sibutramine in a population-based cohort

Objective: Orlistat and sibutramine are widely prescribed antiobesity agents that are approved for 2 years of continuous use. Previous 1-4-year randomized, placebo-controlled trials of these drugs have reported average weight losses of <5 kg, significant adverse effects and attrition rates of up to 60%. The objective of this study was to determine the long-term persistence with orlistat and sibutramine therapy outside a clinical trial setting. Design, setting and patients: Population-based administrative data from British Columbia, Canada, were used to create an inception cohort of orlistat and sibutramine users and determine the 2-year persistence with therapy. Main outcome measure: Persistence with therapy at 2 years. Drug discontinuation was defined as the failure to refill a prescription within 120 days. Patients discontinuing therapy were censored at the 60-day mark. Results: Nearly 17 000 users of orlistat and 3500 users of sibutramine were identified. For both orlistat and sibutramine, 1-year persistence rates were <10% and 2-year persistence rates were 2%. Conclusion: This population-based, retrospective cohort analysis demonstrated very poor long-term persistence rates with orlistat and sibutramine and discontinuation rates that were much higher than those reported in clinical trials.