Observational cohort investigating health outcomes and healthcare costs after metabolic and bariatric surgery: a study protocol

Introduction As the rate of obesity increases, so does the incidence of obesity-related comorbidities. Metabolic and bariatric surgery (MBS) is the most effective treatment for obesity, yet this treatment is severely underused. MBS can improve, resolve, and prevent the development of obesity-related comorbidities; this improvement in health also results in lower healthcare costs. The studies that have examined these outcomes are often limited by small sample sizes, reliance on outdated data, inconsistent definitions of outcomes, and the use of simulated data. Using recent real-world data, we will identify characteristics of individuals who qualify for MBS but have not had MBS and address the gaps in knowledge around the impact of MBS on health outcomes and healthcare costs.Methods and analysis Using a large US employer-based retrospective claims database (Merative), we will identify all obese adults (21+) who have had a primary MBS from 2016 to 2021 and compare their characteristics and outcomes with obese adults who did not have an MBS from 2016 to 2021. Baseline demographics, health outcomes, and costs will be examined in the year before the index date, remission and new-onset comorbidities, and healthcare costs will be examined at 1 and 3 years after the index date.Ethics and dissemination As this was an observational study of deidentified patients in the Merative database, Institutional Review Board approval and consent were exempt (in accordance with the Health Insurance Portability and Accountability Act Privacy Rule). An IRB exemption was approved by the wcg IRB (#13931684). Knowledge dissemination will include presenting results at national and international conferences, sharing findings with specialty societies, and publishing results in peer-reviewed journals. All data management and analytic code will be made available publicly to enable others to leverage our methods to verify and extend our findings.