Determinants of Obesity-Related Kidney Dysfunction Remission after Bariatric Surgery

Introduction : Bariatric surgery was demonstrated to improve obesity-related kidney dysfunction (ORKD). However, the mechanisms underlying ORKD remittance or persistence remain unclear. This study aimed to explore the factors associated with proteinuria remission after bariatric surgery. Methods : A cohort of 39 patients with obesity and proteinuria was followed up for an average of 21.3 ± 4.6 months after bariatric surgery. Pre- and post-surgical assessments included the evaluation of weight-related and kidney-related outcomes. Results : After bariatric surgery, there was a significant reduction in body mass index (BMI) (41.0 ± 9.5 to 26.5 ± 4.6 kg/m², p < 0.05) with a total weight loss (TWL) of 38.5 ± 11.8%. Significant reductions in proteinuria (Δ43.0 ± 35.6%; 352.1 ± 761.5 to 144.2 ± 142.9 mg/24h, p < 0.05) and albuminuria (Δ14.3 ± 81.8%; 137.4 ± 485.9 to 43.7 ± 106.1 mg/24h; p < 0.01) were also observed. Higher pre-operative percentage of albuminuria predicted a greater post-operative reduction in albuminuria (HR: 1.979; 95% CI: 0.686 to 3.272; p < 0.05). Patients with persistent proteinuria (25.6%; n  = 10) despite weight loss were predominantly males (79.3% vs 40.0%, p  = 0.004) with lower serum creatinine levels (0.62 ± 0.07 mg/dL vs. 0.72 ± 0.13 mg/dL, p  < 0.05) and greater CKD-EPI eGFR (117.4 ± 8.8 vs. 104.8 ± 12.4 mL/min/1.73m², p  = 0.005). Conclusion : Bariatric surgery in patients with ORKD resulted in kidney dysfunction remission or significant reductions in proteinuria and albuminuria. Despite weight loss, persistent proteinuria can still be observed suggesting the presence of underlying kidney structural damage that limits kidney dysfunction full recovery.