Evaluation of Intraoperative Gentamicin Bladder Irrigation for Mitigation of Urinary Tract Infections After Kidney Transplantation: A Propensity Score-Matched Analysis of a Randomized Controlled Trial.

Abstract

Background: Urinary tract infections (UTIs) remain the leading infectious complication after kidney transplantation. We evaluated intraoperative gentamicin bladder irrigation as a novel preventive strategy.

Methods: In this randomized, double-blind controlled trial at a tertiary transplant center (January-December 2021), 147 kidney transplant recipients were randomized to receive intraoperative bladder irrigation with gentamicin (160 mg/250 mL) or saline during ureteroneocystostomy. Due to baseline imbalances, propensity score matching yielded 49 matched pairs. The primary endpoint was UTI incidence within 30 days post-transplant, defined by both microbiological (≥ 10⁵ CFU/mL) and clinical criteria.

Results: UTI incidence was 26.5% (13/49) in controls versus 16.3% (8/49) with gentamicin (absolute risk reduction 10.2%, p=0.325). The number needed to treat was 10 overall. Striking sex-specific differences emerged: females demonstrated 40.7% baseline UTI risk versus 14.1% in males (p=0.004). Gentamicin efficacy varied markedly by sex, with the NNT of 5 for females (50.0%-30.8%) versus 17 for males (17.1%-11.1%). Living donor recipients showed greater benefit (NNT = 7) than deceased donor recipients (NNT = 23). No adverse events were attributable to gentamicin, with similar rates of bacteremia and surgical site infections between groups.

Conclusions: Intraoperative gentamicin bladder irrigation safely reduced early post-transplant UTIs by 38.5%, with efficacy in female recipients. While underpowered for statistical significance, the clinically meaningful effect size and excellent safety profile support considering this intervention for high-risk recipients, especially females, pending larger confirmatory trials.