CSEM2408 - CSEM General Stream Oral Abstract Presentations - A Cost-Effectiveness Analysis of Medical and Surgical Weight Management Strategies for Obesity in Canada

Blinded Abstract: Importance: Despite established weight management approaches in Canada, cost-effectiveness remains unclear for new medications like tirzepatide compared to existing therapies and bariatric surgery. This analysis aims to inform policy makers, practitioners and patients.

Objectives: To evaluate the cost-effectiveness of sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), semaglutide, and tirzepatide, all combined with health behaviour intervention (HBI), compared to the standard of care for treating obesity in Canadian adults.

Methods: We employed a Markov model with a 40-year time horizon with health states reflecting obesity-related complications. Interventions included SG, RYGB, tirzepatide (dosages: 5mg, 10mg, 15mg), and semaglutide (dosage: 2.4mg), each combined with HBI, compared to HBI alone. Data on treatment effects, transition probabilities, health state utilities, and costs were sourced from published literature, manufacturers, and government databases. Effectiveness was measured in quality-adjusted life years (QALYs) and costs from the Canadian healthcare system perspective in 2024 Canadian dollars. Future costs and benefits were discounted at 3% annually. The main outcome was the incremental cost-effectiveness ratio (ICER), with a strategy deemed cost-effective if the ICER was less than CAD 50,000 per QALY.

Results: From a Canadian healthcare system perspective, at a willingness-to-pay threshold of CAD 50,000 per QALY, SG emerged as the most cost-effective intervention (ICER of CAD 45,413 per QALY gained) compared to the standard of care (HBI). Results were robust to sensitivity analyses varying annual costs, QALYs, and clinical probabilities.

Conclusion: Under current conditions, SG appears to be the most cost-effective among medical and surgical obesity treatments for Canadian adults.