Prospective blinded laboratory assessment of prophylactic antibiotic compliance in a pediatric outpatient setting

Prophylactic antibiotics are commonly used to prevent urinary tract infections in children with conditions such as vesicoureteral reflux. Patient compliance with antibiotics is salient, given the effects that noncompliance can have on development of antibiotic resistance and outcomes of clinical trials. Prior series have shown variable compliance (17% to 70%). However, no study has used objective methods. We hypothesized that direct measurement of urine antibiotic levels can reveal poor compliance.

During a pediatric urology clinic visit patients 0 to 18 years old taking trimethoprim prophylaxis for any urological diagnosis were invited to participate in the study. They were unaware of any potential urine testing before the visit. Urine was sent for chromatography to quantify trimethoprim levels. Parents also completed a compliance self-assessment.

Of patients invited to participate 97% consented (54 patients). Of the patients 91% were compliant based on urine levels. Factors not associated with compliance included age, gender, self-report of compliance, duration of time on antibiotics, insurance status and history of breakthrough infection, surgery, pyelonephritis or hospitalization.

This study demonstrates the highest compliance reported for children taking prophylactic antibiotics to prevent urinary tract infection. We attribute this unexpected result to the discussion by specialists of 1 problem for the duration of an office visit. All education in this study was part of clinical care. Thus, our results should be generalizable to nonstudy environments. Future studies should confirm whether this high level of compliance can be achieved by nephrologists and pediatricians. If such compliance cannot be achieved at nonsurgical clinics, then early referral to a pediatric urologist may be warranted.