Relationships Between Metabolic and Bariatric Surgery and Adverse Kidney Outcomes: An Analysis of a Retrospective Cohort

Objective: Obesity is associated with an increased risk of chronic kidney disease. Metabolic and bariatric surgery (MBS) is currently the most effective intervention for sustained weight loss and may reduce the risk of obesity-associated kidney disease. This study examined the relationships between MBS and adverse kidney outcomes. Methods: This retrospective cohort analysis included 4322 patients with obesity, with or without type 2 diabetes mellitus (T2D), who underwent MBS, and 30,919 nonsurgical control patients from a large health system within the state of Indiana. A primary kidney composite [≥ 1 estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m², ≥ 1 eGFR measurement with a ≥ 40% decrease from baseline, or kidney failure-related death], as well as secondary and tertiary composite and individual outcomes were assessed. Multivariable Cox regression models with and without inverse propensity of treatment weighting were employed to assess associations between MBS and incidence rate for each kidney outcome compared with nonsurgical controls. Results: The mean (standard deviation) follow-up duration was 6.1 (4.5) years. MBS was associated with a 53% (HR: 0.47; 95% CI: 0.42, 0.52; p < 0.001) and 48% (HR: 0.52; 95% CI: 0.46, 0.60; p < 0.001) lower incidence of the primary kidney composite outcome in patients with and without T2D, respectively, and 48%–56% lower risks for the secondary and tertiary outcomes, regardless of T2D status, compared to controls. Conclusions: MBS was associated with markedly lower risks for adverse kidney outcomes in patients with obesity. These results support the potential for MBS as a weight loss intervention to preserve kidney function in patients with obesity, both with and without T2D.