Costs and outcomes of increasing access to bariatric surgery for obesity: cohort study and cost-effectiveness analysis using electronic health records

Objectives: To estimate costs and outcomes of increasing access to bariatric surgery (BS) in obese adults and in population sub-groups of gender, age, deprivation, comorbidity and obesity category. Methods: Cohort study using primary care electronic health records, with linked hospital utilisation data, for 3,045 participants who received BS, and 247,537 participants who did not receive surgery. Epidemiological analyses informed a probabilistic Markov model to compare BS, including equal proportions with adjustable gastric banding, gastric bypass and sleeve gastrectomy, with standard non-surgical management of obesity. Outcomes were quality adjusted life years (QALYs) and net monetary benefits at a threshold of £30,000 per QALY. Results: In a UK population of 250,000 adults, there may be 7,163 people with morbid obesity including 1,406 with diabetes. The immediate cost of 1,000 bariatric surgical procedures is £9.16 million, with incremental discounted lifetime health care costs of £15.26 (95% range £15.18 to 15.36) million. Patient years with diabetes mellitus will decrease by 8,320 (8,123 to 8,502). Incremental quality adjusted life years (QALYs) will increase by 2,142 (2,032 to 2,256). The estimated cost per QALY gained is £7,129 (£6,775 to £7,506). Net monetary benefits will be £49.02 (£45.72 to £52.41) million. Estimates are similar for subgroups of gender, age and deprivation. BS remains cost-effective if the procedure is twice as costly, or if intervention effect declines over time. Conclusions: Diverse obese individuals have capacity to benefit from BS at acceptable cost. BS is not cost-saving but increased health-care costs are exceeded by health benefits to obese individuals.