Determinants and Frequency of Acute Kidney Injury After Endoscopic Retrograde Cholangiopancreatography

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is commonly performed for pancreaticobiliary disorders. However, renal dysfunction may occur after the procedure and can influence clinical outcome. This study was planned to estimate the frequency of acute kidney injury (AKI) following ERCP and to assess the clinical and laboratory factors associated with its occurrence. Methods: This observational analytical study was conducted at the Department of Gastroenterology, Lahore General Hospital, Lahore, from January 2025 to March 2026. A total of 296 patients undergoing ERCP for choledocholithiasis, obstructive jaundice, biliary stricture, or pancreaticobiliary malignancy were enrolled by non-probability consecutive sampling. Patients with end-stage renal disease, pre-existing AKI, prior renal replacement therapy, renal transplant, or unclear repeat ERCP records were excluded. Results: AKI was observed within 48 hours after ERCP in 52 (17.6%; 95% CI 13.7-22.3%) patients. Most AKI cases were KDIGO Stage 1 (37/52, 71.2%), followed by Stage 2 (9/52, 17.3%) and Stage 3 (6/52, 11.5%). Patients who developed AKI had a higher mean age than those without AKI (61.2 ± 13.8 vs. 52.4 ± 14.9 years, p = 0.001). The Charlson Comorbidity Index (CCI) was also significantly raised in the AKI group (5 (IQR 3-6) vs. 3 (IQR 2-4); p < 0.001). Acute cholangitis was the commonest ERCP indication among patients with AKI as compared with those without AKI (31/52 (59.6%) vs. 58/244 (23.8%), p < 0.001). Baseline renal function was worse among patients who developed AKI, with higher serum creatinine (1.42 ± 0.68 vs. 0.84 ± 0.31 mg/dL) and lower estimated glomerular filtration rate (58.4 ± 28.7 vs. 84.6 ± 24.3 mL/min/1.73 m²), with both comparisons showing statistical significance (p < 0.001). Mean hospital stay was also longer in patients with AKI (9.4 ± 5.1 vs. 6.1 ± 3.6 days, p < 0.001). On multivariable analysis, CCI, acute cholangitis, reduced eGFR, raised bilirubin, low albumin level, and exposure to nephrotoxic drugs or intravenous contrast were identified as independent determinants of post-ERCP AKI. Conclusion: Post-ERCP AKI is an important renal complication and was mainly associated with greater comorbidity burden, acute cholangitis, reduced baseline renal function, raised bilirubin, low serum albumin, and prior nephrotoxic drug or intravenous contrast exposure. Careful pre-procedural renal assessment and early post-procedural monitoring may help identify high-risk patients and reduce adverse clinical outcomes.