Abstract
INTRODUCTION: Acute kidney injury (AKI) is a potentially severe complication after bariatric surgery, associated with increased morbidity, prolonged hospitalization, and impaired long-term renal outcomes. However, the reported prevalence of postoperative AKI and its risk factors in adults with obesity remain inconsistent across studies. AIM: This systematic review and meta-analysis aimed to estimate the pooled prevalence of AKI after bariatric surgery and identify associated risk factors in adults with obesity. MATERIALS AND METHODS: A comprehensive literature search of PubMed, Embase, and the Cochrane Library databases was performed from inception to March 1, 2025, following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Observational studies reporting AKI prevalence or risk factors in adults with obesity undergoing bariatric surgery were included. Two reviewers independently screened the studies, extracted data, and assessed their quality using the Newcastle-Ottawa scale. Random-effects models were applied to calculate pooled prevalence and odds ratios (ORs). Subgroup, sensitivity analyses, and publication bias assessments were also conducted. RESULTS: A total of 11 studies involving 242 159 patients were analyzed. The overall pooled prevalence of postoperative AKI was 2.5% (95% CI, 1.8-3.1), with substantial heterogeneity (I² = 98.1%). Subgroup analyses showed higher AKI rates in case-control studies, small sample studies, and studies based on the AKI Network criteria. Significant risk factors for AKI included male sex (OR, 2.15; 95% CI, 1.54-3.01), pre-existing renal insufficiency (OR, 5.33; 95% CI, 1.4-20.26), hypertension (OR, 1.74; 95% CI, 1.37-2.21), hyperlipidemia (OR, 1.53; 95% CI, 1.04-2.24), and elevated body mass index (OR per unit increase, 1.05; 95% CI, 1.02-1.09). Diabetes and age were not significantly associated with AKI across the studies. CONCLUSIONS: AKI occurs in approximately in 2.5% of adults with obesity following bariatric surgery. Identifying high-risk patients based on clinical factors may help guide perioperative renal protection strategies.