Bariatric Surgery and Renal Function: A Mid-Term Prospective Analysis of Estimated Glomerular Filtration Rate Dynamics in Adults with and without Diabetes Mellitus.

BACKGROUND

Obesity is associated with a range of medical problems, including impaired renal function. Type 2 diabetes mellitus (T2DM), independently, exerts a direct and multifactorial impact on renal health. This study evaluates and compares the effects of metabolic bariatric surgery (MBS) on renal function in patients with and without T2DM.

METHODS

This prospective cohort study followed patients undergoing MBS over three years, stratified by T2DM status. Participants were matched using propensity scores (PS), and postoperative trajectories of creatinine-based estimated glomerular filtration rate (eGFR) were compared. Generalized estimating equation (GEE) method was employed to identify factors significantly associated with changes in eGFR over time.

RESULTS

A total of 1895 participants (83% women), including 770 PS-matched individuals, were enrolled in the study. All participants had a baseline eGFR ≥ 60 mL/min/1.73m2. Across both unmatched and matched cohorts, and irrespective of T2DM status, eGFR improved over the three-year follow-up, with no significant between-group differences or interactions observed. Multivariable analysis identified older age, being a woman, higher baseline eGFR, and undergoing sleeve gastrectomy (SG) as negative correlates of eGFR improvements over time.

CONCLUSION

Renal function improved following MBS, regardless of T2DM status. Furthermore, older age, being a woman, higher baseline eGFR, and undergoing SG were associated with less eGFR improvements.