Perioperative Outcomes of Bariatric Surgery Across Chronic Kidney Disease Stages: National Inpatient Sample Analysis 2016-2022

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• Picked for Bariatric and Metabolic Surgery (top studies of the week, 8 November 2026): National study informs bariatric operative risk by CKD stage

Abstract

BACKGROUND: Bariatric surgery is increasingly performed in patients with chronic kidney disease (CKD), but perioperative outcomes across CKD severity remain incompletely characterized. We evaluated stage-specific perioperative outcomes after bariatric surgery in a contemporary national cohort. METHODS: We analyzed 284,230 adult bariatric surgery hospitalizations from the National Inpatient Sample (2016-2022), stratified as no CKD, CKD stages 1-2, 3, 4, 5, and dialysis-dependent end-stage renal disease (ESRD). The primary outcome was in-hospital mortality. Secondary outcomes included acute kidney injury, major bleeding, sepsis, acute respiratory failure, new dialysis, length of stay, and hospital charges. Survey-weighted multivariable regression (the primary models) evaluated associations between CKD stage and outcomes. A separate fully specified mortality model included CKD stage, age group, sex, diabetes, frailty, procedure type, and hospital volume. RESULTS: CKD was documented in 3.4% of hospitalizations. Crude mortality was 0.3% without CKD, 2.0% in stage 3, 5.9% in stage 4, and 4.9% in dialysis-dependent ESRD. In the primary models, stage 4 CKD (adjusted odds ratio [aOR] 3.85, 95% CI 2.58-5.75) and ESRD (aOR 7.34, 95% CI 5.33-10.12) were associated with greater mortality, whereas stages 1-3 were not significantly associated with mortality after adjustment. Advanced CKD was also associated with greater bleeding, sepsis, respiratory failure, and resource utilization. Stage 4 CKD was strongly associated with new dialysis (primary model aOR 16.47, 95% CI 9.19-29.51). Sleeve gastrectomy had lower crude event rates than Roux-en-Y gastric bypass across CKD strata, although the procedure-by-stage interaction for a composite adverse event was modest (P = 0.048). CONCLUSION: Advanced CKD, particularly stage 4 disease and dialysis-dependent ESRD, was associated with substantially greater in-hospital risk after bariatric surgery. These findings support CKD-stage-specific risk assessment, multidisciplinary perioperative management, and individualized procedural planning. Observed differences between procedures should be interpreted cautiously given the potential for residual confounding.

Abstract as published, via PubMed.