New-Onset Type 2 Diabetes after Bariatric Surgery: A Matched Cohort Study

Abstract

Introduction: The objective of this study is to determine the difference in rates of new-onset type 2 diabetes (T2D) for individuals who have had metabolic and bariatric surgery (MBS) and similar individuals who did not have MBS, and to determine whether differences in new-onset T2D differ depending on whether the individual had prediabetes at baseline. Methods: This study used data from a large US employer-based retrospective claims database from 2016 to 2021 (analysis completed in 2023). Individuals who did and did not have MBS were matched 1:1 on index year, sex, age, health plan type, region, BMI, baseline healthcare costs, other obesity-related comorbidities, prediabetes diagnosis, and inpatient admissions in the year before the index date. New-onset T2D was examined at 1 (18,752 matches) and 3 (5,416 matches) years after the index date and stratified by baseline prediabetes. Results: Among the full cohort of individuals with and without prediabetes at baseline, 0.1% and 2.7% of individuals who had did and did not have MBS developed T2D within one year after the index date, respectively (difference = 2.6, 95% CI 2.4 to 2.8), and 0.3% and 8.4% of individuals who did and did not have MBS developed T2D within three years after the index date, respectively (difference = 8.1, 95% CI 7.3 to 8.8). The difference in new-onset T2D was greatest among individuals with prediabetes at baseline. Conclusions: This study demonstrated patients with obesity and without T2D who undergo MBS are significantly less likely to develop new-onset T2D compared to matched non-MBS patients.