Vesicoureteral Reflux and Antibiotic Prophylaxis: Why Cohorts and Methodologies Matter

Published cohorts of children with vesicoureteral reflux placed on antibiotic prophylaxis differ in baseline characteristics and methodology. These data have been combined in meta-analyses to derive treatment recommendations. We analyzed these cohorts in an attempt to understand the disparate outcomes reported.

A total of 18 studies were identified from 1987 to 2013. These series retrospectively or prospectively evaluated children with vesicoureteral reflux who were on long-term antibiotic prophylaxis. Presenting demographic data, criteria and methods of evaluation were tabulated. Outcomes were compared, specifically recurrent urinary infections and renal scarring.

Significant differences identified in baseline characteristics included gender, circumcision status and reflux grade, and differences in methodology included evaluation of bowel and bladder dysfunction, method of urine collection, definition of urinary infection, measurement of compliance and means of identifying renal scarring. Cohorts with larger numbers of uncircumcised boys had more breakthrough urinary infections. Infection and renal scarring rates were higher in series with higher grades of reflux. Bagged urine specimens were allowed in 6 series, rendering the data suspect. Children with bowel and bladder dysfunction were excluded from 3 cohorts, and bowel and bladder dysfunction was correlated with outcome in only 1 cohort. Compliance was monitored in only 6 studies.

Subpopulations and methodologies vary significantly in published series of children with vesicoureteral reflux on antibiotic prophylaxis. It is inappropriate to combine outcomes data from these series in a meta-analysis, which would serve to blur distinctions between these subpopulations. Broad recommendations or guidelines based on meta-analyses should be viewed with caution.