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Cumulative incidence of febrile urinary tract infection after discontinuation of continuous antibiotic prophylaxis in young males with high-grade vesicoureteral reflux: a retrospective cohort study
Kikachukwu Otiono, MD1, Laura Harkness, MD1, Deepti Reddy, MSc2, Mei Han, MSc2, Macarena Costabel, MD3, Yuding Wang, MD, MSc3, Pavel Geier, MD, PhD4, Luis Guerra, MD, MSc3.
1Division of Urology, University of Ottawa, Ottawa, ON, Canada, 2Clinical Research Unit, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada, 3Division of Pediatric Urology, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada, 4Division of Pediatric Nephrology, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada.
BackgroundContinuous antibiotic prophylaxis (CAP) is widely used in the management of high-grade vesicoureteral reflux (VUR) in young children. The PREDICT trial demonstrated that CAP reduces the risk of febrile urinary tract infection (fUTI) in infants with grade III–V VUR, with a number needed to treat of 7 (Morello et al, 2023). However, the optimal duration of CAP and the safety of its discontinuation remain poorly defined. Existing studies include mixed-sex cohorts, yet sex-based differences in fUTI risk are well established: the Swedish Reflux Trial demonstrated that recurrent fUTI was significantly more common in girls than boys with dilating VUR (Brandström et al, 2010). No study has specifically examined CAP discontinuation outcomes in young males with high-grade VUR – a population with distinct risk profile and potentially favourable natural history. The objective of this study was to assess the cumulative incidence of fUTI after CAP discontinuation in males under 24 months of age with high-grade VUR.
MethodsA single-centre retrospective chart review was conducted of males less than 24 months of age diagnosed with grade III–V VUR who were started on and subsequently discontinued from CAP. VUR was diagnosed primarily by voiding cystourethrogram (VCUG) and confirmed VUR resolution was not required prior to discontinuation. Patients were identified from January 2010 to January 2026, with a minimum of 3 months post-discontinuation follow-up required for inclusion. fUTI was defined as fever > 38°C with pyuria on urinalysis and positive urine culture (≥100,000 CFU/mL). The primary outcome was cumulative incidence of fUTI after CAP discontinuation.
ResultsOf 184 patients screened, 91 met eligibility criteria; the most common exclusion reasons were secondary VUR, age at discontinuation ≥24 months, and incomplete follow-up. Median age at VUR diagnosis was 1 month (IQR 0–3) and median age at CAP discontinuation was 16 months (IQR 13–19). Most patients were uncircumcised (62.6%), and 45.6% had bilateral VUR. VUR grade distribution was grade III 30.0%, grade IV 40.0%, and grade V 28.9%. Hydronephrosis was present on baseline renal-bladder ultrasound in 84.6%. The most common reason for discontinuation was routine clinical decision-making based on age or clinical stability (77.3%). Median follow-up after discontinuation was 29 months (IQR 14–59). Eleven patients developed fUTI, yielding a cumulative incidence of 12.1% (95% CI 6.9–20.4%). Median time from discontinuation to fUTI was 6.7 months (IQR 2–19.6; range 1–33.9).
ConclusionIn this retrospective cohort of pediatric males with high-grade VUR, the cumulative incidence of fUTI after CAP discontinuation was 12.1%, consistent with the 11% post-cessation rate reported in a large multi-grade cohort (Abdulfattah et al, 2025). These findings suggest that clinician-guided CAP discontinuation before 24 months of age may be well tolerated in selected males with high-grade VUR, even without confirmed VUR resolution. Prospective studies incorporating time-to-event analyses and standardized discontinuation criteria are needed to define which patients remain at meaningful risk for fUTI after CAP cessation.
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