Renal Outcomes After Sleeve Gastrectomy versus Gastric Bypass in Patients with Nephropathy: Results from a Retrospective Study.

INTRODUCTION: The influence of metabolic bariatric surgery (MBS) on renal damage remains poorly understood. Data on the impact of different types of MBS on renal markers is limited. This study analyzes the effects of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) on traditional (urinary albumin-creatinine ratio (uACR), estimated glomerular filtration rate (eGFR)) and new markers (serum uromodulin (sUMOD), serum kidney injury molecule-1 (sKIM-1)) of kidney function in a retrospective cohort of patients with nephropathy. METHODS: 50 patients (RYGB n = 25; SG n = 25) with renal involvement, defined as microalbuminuria (uACR > 3 mg/mmol) and/or reduced eGFR (< 60 ml/min) were included. Patients were matched for sex, age, body mass index (BMI) and glycemic control. Kidney function was assessed using creatinine, cystatin C, eGFR, uACR, sUMOD and sKIM-1. RESULTS: After a mean follow-up of 28.8 ± 6.1 months, renal involvement completely resolved in 48% after SG (p<.001) compared to 68% after RYGB (p<.001). UACR decreased after both procedures (SG -9.9 ± 23.2 mg/mmol, p=.002; RYGB − 14.4 ± 28.9 mg/mmol, p<.001) without a difference between procedures (p=.923). SUMOD and sKIM-1 improved significantly after SG (p=.025, p=.028). CONCLUSIONS: In this study, MBS was associated with improved nephropathy outcomes, independent of the type of procedure performed. SUMOD emerges as a promising biomarker to predict renal recovery.