P.J. Guidos, A.M. Arlen, T. Leong, M.A. Bonnett, C.S. Cooper

Continuous antibiotic prophylaxis (CAP) is a mainstay of treatment for children with vesicoureteral reflux (VUR). There has been an increasing focus on the effect of antibiotics on gut microbiota and subsequent repercussions on growth. Continuous antibiotic prophylaxis is generally considered safe; however, its impact on growth in children with VUR remains unknown. This objective of this study was to determine whether CAP altered height, weight, or body mass index (BMI) in children with VUR. Children diagnosed with primary VUR were identified. Demographics including weight and height percentiles, BMI and BMI percentiles, age, gender, antibiotic class, prior antibiotic use, urinary tract infection history, and breakthrough infections were tested in univariate and multivariate analyses. Primary outcome was change in BMI as well as weight, height, and BMI percentiles. One hundred eighty patients (146 girls, 34 boys) were prescribed CAP at mean age of 29.2 ± 26.2 months. Mean follow-up on CAP was 4.1 ± 3.3 years, with median follow-up of 3.08 years. Mean increase in weight percentile was 1.49 (2.02 males, 1.37 females; P = 0.46). Mean decrease in height percentile was -4.44 (-2.18 males, -4.95 females; P = 0.51). Age at diagnosis (P = 0.004) and history of prior treatment courses of antibiotics (P = 0.007) were associated with a significant BMI increase (Fig. 1). Body mass index percentile increased from 58.4 to 66.5; however, this increase was only significant in children aged above 1 year (P < 0.0001). Of note, children above 1 year of age were significantly more likely to have a history of prior treatment courses of antibiotics (58% vs 32%; P < 0.0001), and when controlling for prior antibiotic use, the increase in BMI percentile in those over 1 year of age did not reach significance. The use of antibiotics has been associated with alterations in pediatric growth parameters in both animal models and clinical studies. However, little information exists on the impact of prophylactic-dosed antibiotics on growth. While this study is limited by the retrospective analysis and small sample size, it was found that the use of CAP did impact growth parameters, with a stronger effect seen in children who had received prior treatment courses of antibiotics before the infection leading to the initiation of CAP. Continuous antibiotic prophylaxis was correlated with significant increase in BMI in children with prior antibiotic usage and a significant increase in BMI percentile in children aged above 1 year. Continuous antibiotic prophylaxis was also associated with decreased height percentiles, particularly in patients aged less than 1 year, though it did not reach statistical significance. Further analysis is needed to investigate whether these effects on weight, height, and BMI are persistent and clinically significant.