Observation of patients with vesicoureteral reflux off antibiotic prophylaxis: physician bias on patient selection and risk factors for recurrent febrile urinary tract infection.

PURPOSE: Observation off continuous antibiotic prophylaxis is an option for vesicoureteral reflux. We evaluated the characteristics of patients observed off continuous antibiotic prophylaxis and risk factors for febrile urinary tract infection. MATERIALS AND METHODS: We identified children 1 to 18 years old with primary vesicoureteral reflux between January 1, 2010 and December 31, 2010. We excluded patients with prior surgical correction from analysis. We recorded age, gender, race/ethnicity, primary language, insurance carrier, age at vesicoureteral reflux diagnosis, initial presentation and vesicoureteral reflux severity. We quantified bladder and bowel dysfunction with a validated questionnaire if toilet trained. We compared patients off vs on continuous antibiotic prophylaxis with the chi-square test for categorical variables and the Mann-Whitney U test for continuous variables. We used a univariate Cox proportional hazards model to assess predictors of febrile urinary tract infection during observation off continuous antibiotic prophylaxis. RESULTS: Of 529 eligible patients 224 were observed off continuous antibiotic prophylaxis. Patients off continuous antibiotic prophylaxis tended to be older (p <0.001), to be older at diagnosis (p <0.001), to have an initial presentation other than febrile urinary tract infection (p = 0.05), to have nondilating vesicoureteral reflux on most recent cystogram (p <0.001) and to have lower bladder/bowel dysfunction scores if toilet trained (p <0.001). Of the patients off continuous antibiotic prophylaxis a febrile urinary tract infection developed in 19 (8.5%). Risk factors associated with febrile urinary tract infection included initial presentation of multiple febrile urinary tract infections (p = 0.03), older age at diagnosis (p = 0.03) and older age starting observation off continuous antibiotic prophylaxis (p = 0.0003). CONCLUSIONS: Criteria to select patients with vesicoureteral reflux for observation off continuous antibiotic prophylaxis remain poorly defined in the literature. Observation will fail in a subset of patients with vesicoureteral reflux. Physician biases regarding patient selection for observation off continuous antibiotic prophylaxis should be considered when interpreting studies that evaluate treatment strategies.