Long-term risk of renal impairment after complete primary repair of classic bladder exstrophy

Background: This study evaluated the long-term risk of renal impairment and the factors influencing renal function after complete primary repair of classic bladder exstrophy (CBE). Materials and Methods: A retrospective review was conducted for 66 patients with CBE (50 males, 16 females) who underwent complete primary repair between 1998 and 2024. The median follow-up time was 83.5 months (range, 12–324 months). A post hoc power analysis (α =0.05, n = 66, effect size = 0.5) showed a power of 0.98. The primary outcome was the estimated glomerular filtration rate (eGFR) at the final follow-up, with renal impairment defined as < 60 mL/min/1.73 m². Univariate and multivariate analyses assessed associations between renal impairment and key clinical factors. Results: The median eGFR at the last follow-up was 112.4 mL/min/1.73 m² (range 37.31–147.7). Four patients (6.1%) developed renal impairment. Severe hydronephrosis ( P = 0.003), high-grade vesicoureteral reflux ( P = 0.003), febrile urinary tract infection (UTI) ( P = 0.008), and smaller bladder capacity ( P = 0.032) were significantly associated with impaired renal function. Multivariate analysis identified severe hydronephrosis ( P = 0.025; odds ratio [OR] 33.8) and febrile UTI ( P = 0.033; OR 6.34) as independent predictors. Conclusions: Long-term renal function remained stable in most patients after complete primary repair of CBE, although 6% experienced renal impairment. Severe hydronephrosis, high-grade reflux, febrile UTI, and reduced bladder capacity were essential predictors, emphasizing the need for close monitoring and timely management.