Antimicrobial prophylaxis for urinary tract infections: implications for adherence assessment.

Abstract

BACKGROUND\nContinuous antimicrobial prophylaxis (prophylaxis) is associated with a reduction in recurrent urinary tract infections in children with vesicoureteral reflux. However, adherence to daily medications has been shown to be poor.\n\n\nOBJECTIVE\nTo determine patient/caregiver factors associated with non-adherence and to determine whether adherence alters the effect of prophylaxis on recurrent UTIs and renal scarring.\n\n\nSTUDY DESIGN\nWe conducted a secondary analysis of the Randomized Intervention for Children with Vesicoureteral Reflux trial. We stratified adherence scores into quartiles to assess trends within the data. We assessed predictors of non-adherence using ordinal logistic regression. We then examined the efficacy of prophylaxis stratified by adherence quartiles.\n\n\nRESULTS\nSix hundred patients were included in the analysis. The quartiles of adherence were as follows: 1st quartile-0-70% adherence; 2nd quartile-71-91% adherence; 3rd quartile-92-96% adherence; and 4th quartile->96% adherence. Neither demographic factors nor disease severity was associated with non-adherence. In the subanalysis of patients who were toilet trained at baseline, increasing bladder and bowel dysfunction (BBD) symptom score was associated with non-adherence (adjusted odds ratio, aOR\xa0=\xa01.1, 95% confidence interval [CI] 1.0-1.2). Patients least adherent were 2.5 times more likely (95%CI 1.1-5.6) to have a recurrent UTI compared with patients most adherent. After controlling for treatment arm, age, sex, degree of reflux, BBD, and number of UTIs, patients least adherent (taking the study medication less than <70% of the time) were at highest risk for renal scarring (aOR\xa0=\xa024.2, 95%CI 3.0-197). In contrast, among the most adherent quartile, the probability of renal scarring was highest in those assigned prophylaxis (16.2% compared with 1.7% in those most adherent to placebo).\n\n\nCONCLUSIONS\nAdherence is distinctly related to clinical outcomes in children with VUR. Non-adherence is common and represents a distinct clinical entity that is associated with renal scarring. Adherence should be assessed in prophylaxis management algorithms.