PURPOSE: United States has the highest prevalence of overweight (66.30%) and obese individuals (32.20%), amongst all developed countries. The objective of this study was to conduct a head-to-head comparison of behavioral therapy, orlistat, and sibutramine for the long term treatment of obesity.
METHOD: Cost effectiveness (CE) decision analysis model and incremental CE ratio was developed using data from published randomized controlled trials and primary data collection. Three decision analyses models were developed, one comparing three alternatives simultaneously using average weight reduction as the final outcome and another with reaching a goal of 5% weight reduction. The third model included a comparison of two drugs with reaching a goal of 10% weight reduction. Cost of each outcome was derived by combining, direct medical costs including physician visits and prescription drug cost, and indirect cost associated with productivity loss for a year. Physician fees and drug costs were determined by contacting at least 5 pharmacy and physician offices. Indirect cost was computed using median US income and additional work-days lost due to obesity. One-way and two-way sensitivity analyses were performed for cost of orlistat as an OTC product and percentage of patients achieving 5% and 10% weight reduction.
RESULT: Mean average percent weight reduction and total cost for behavioral therapy, orlistat, and sibutramine was 3.0%, 5.9%, 7.3%, and $8,088, $12,217, $10,285, respectively. The model for comparing three therapies simultaneously revealed sibutramine pharmacotherapy as the most cost effective option to achieve average weight reduction. Behavioral therapy demonstrated to be the cost effective option for achieving a predetermined goal of 5% weight reduction whereas sibutramine was cost effective for 10% weight reduction. One-way sensitivity analysis using cost of orlistat as an OTC product and a two-way sensitivity analyses for probabilities of obese patients achieving 5% and 10% weight reduction, duplicated earlier results, demonstrating robustness of the model. ICER for switching from behavioral therapy to orlistat was $1,423 and for sibutramine it was $510.
CONCLUSION: Behavioral therapy may be a cost effective option for achieving an average predetermined weight reduction goal of 5%, but for a higher average weight reduction goal of 10%, sibutramine pharmacotherapy was cost effective. Moreover, this substantial health benefit of higher weight reduction can be attained at relatively lower incremental cost of $510 per year.
