Kidney Week

Abstract: SA-PO0500

Effect of Bariatric Surgery on Kidney Function in Morbid Obesity: Reduction of Glomerular Hyperfiltration and Albuminuria in a 10-Year Retrospective Cohort

Session Information

• CKM: Clinical - Screening, Population Management, Care Disparities, and Patient-Centered Outcomes
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Cardiovascular-Kidney-Metabolic Health

• 602 Cardiovascular-Kidney-Metabolic Health: Clinical

Authors

• Gonzalez Medina, Ana Cristina, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Ana Cristina Gonzalez Medina, MD

• Torres, Jesus, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Jesus Torres

• Chavez Manzanera, Emma Adriana, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Emma Adriana Chavez Manzanera, MD

• Correa-Rotter, Ricardo, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Ricardo Correa-Rotter, MD

Background

Morbid obesity drives CKD through glomerular hyperfiltration, inflammation, and podocyte injury. Although bariatric surgery (BS) improves metabolic outcomes, its long-term renal effects in real-world practice remain incompletely characterized.

Methods

Retrospective cohort of 1,477 adults with obesity (BMI ≥30kg/m2) and baseline eGFR at a tertiary Institute in Mexico, between 2015–2024. Of these, 171 (11.6%) underwent BS: 74.9% Roux-en-Y gastric bypass (RYGB), 23.4% sleeve gastrectomy (SG). eGFR was calculated by CKD-EPI and categorized per KDIGO 2024; hyperfiltration was defined as eGFR >120 mL/min/1.73m2; albuminuria by UACR. Follow-up up to 10 years. Mann-Whitney U, chi-square, and Wilcoxon signed-rank tests were used.

Results

Mean age was 43.4±12.1 years, 68.3% women, BMI 42.7±8.4kg/m2. At baseline, 33.3% met at least one criterion for kidney damage, with hyperfiltration being most frequent (23.8%). Baseline eGFR was similar between groups (107.9±16.9 vs. 104.1±22.0 mL/min/1.73m2, p=0.08). Non-BS patients showed progressive eGFR decline (Δ −5.68 mL/min at year 5, p<0.001); BS patients remained stable (Δ +0.22, p=0.929), with mean eGFR of 103.3±15.1 vs. 96.0±24.9 mL/min/1.73m2 at year 5. Among BS patients with baseline hyperfiltration (n=42), eGFR fell significantly (Δ −10.65 at year 5, p=0.023), with 50% achieving resolution. BS reduced UACR from 45.8 to 13.6 mg/g at year 1 (p=0.001); non-BS showed no significant change. RYGB showed greater renal preservation than SG. Nineteen deaths occurred, all in the non-BS group.

Conclusion

In this large real-world cohort with up to 10 years of follow-up, BS was associated with preservation of kidney function and significant reduction in UACR compared with non-surgical management, suggesting a potential nephroprotective effect in severe obesity. Findings should be interpreted cautiously given the retrospective design, incomplete UACR data, and lack of multivariable adjustment, but it provides long-term renal outcome data after BS in a Mexican population, a group underrepresented in the bariatric-nephrology literature despite a high burden of obesity and CKD.