Eleven RCTs met the inclusion criteria (n=2,046 children). Three RCTs adequately concealed allocation, two RCTs did not conceal allocation and it was unclear whether allocation was concealed in six RCTs. Only two RCTs were double blind, five RCTs were not blinded and only radiological outcome assessors were blinded in three RCTs. Five RCTs performed intention-to-treat analysis; it was unclear in the remaining RCTs. Losses to follow-up were generally low (0 to 22%) at six months to four years of follow-up.
The effect of antibiotic prophylaxis on recurrence of symptomatic urinary tract infection was not statistically significantly different from placebo or no treatment (RR 0.83 95% CI 0.66 to 1.05; seven trials; n=1,717 children), with no apparent heterogeneity between the trials (I2=0%).
Antibiotic prophylaxis significantly reduced repeat positive urine culture compared with placebo or no treatment (RR 0.50, 95% CI 0.34 to 0.74; 11 trials; n=2,046 children), but heterogeneity was significant (I2=76%).
There was no significant difference in new or deteriorated renal scars between antibiotic prophylaxis and placebo or no treatment (RR 0.95, 95% CI 0.51 to 1.78; seven trials; n=1,093 children), with no heterogeneity between the trials (I2=0%).
Three trials reported on adverse events, and recorded very low event rates (2 to 7.3%), which were mainly mild.
Sensitivity and subgroup analyses did not change the findings on recurrence of symptomatic urinary tract infection, except on the level of trial quality; adequately concealed studies showed statistically significant reduction in recurrent symptomatic urinary tract infection (RR 0.68, 95% CI 0.48 to 0.95; number of studies not stated). A subgroup analysis on patients without vesico-ureteric reflux demonstrated non-significant reduction in risk of repeat positive urine culture (P=0.17), although there was significant heterogeneity between the studies (I2=62%).
There was no evidence of publication bias.