title: Recurrent urinary tract infections in children: risk factors and association with prophylactic antimicrobials.
abstract: BACKGROUND
  The evidence regarding risk factors for recurrent urinary tract infection (UTI) and the risks and benefits of antimicrobial prophylaxis in children is scant.
  
  
  OBJECTIVE
  To identify risk factors for recurrent UTI in a pediatric primary care cohort, to determine the association between antimicrobial prophylaxis and recurrent UTI, and to identify the risk factors for resistance among recurrent UTIs.
  
  
  METHODS
  From a network of 27 primary care pediatric practices in urban, suburban, and semirural areas spanning 3 states, a cohort of children aged 6 years or younger who were diagnosed with first UTI between July 1, 2001, and May 31, 2006, was assembled. Time-to-event analysis was used to determine risk factors for recurrent UTI and the association between antimicrobial prophylaxis and recurrent UTI, and a nested case-control study was performed among children with recurrent UTI to identify risk factors for resistant infections.
  
  
  METHODS
  Time to recurrent UTI and antimicrobial resistance of recurrent UTI pathogens.
  
  
  RESULTS
  Among 74 974 children in the network, 611 (0.007 per person-year) had a first UTI and 83 (0.12 per person-year after first UTI) had a recurrent UTI. In multivariable Cox time-to-event models, factors associated with increased risk of recurrent UTI included white race (0.17 per person-year; hazard ratio [HR], 1.97; 95% confidence interval [CI], 1.22-3.16), age 3 to 4 years (0.22 per person-year; HR, 2.75; 95% CI, 1.37-5.51), age 4 to 5 years (0.19 per person-year; HR, 2.47; 95% CI, 1.19-5.12), and grade 4 to 5 vesicoureteral reflux (0.60 per person-year; HR, 4.38; 95% CI, 1.26-15.29). Sex and grade 1 to 3 vesicoureteral reflux were not associated with risk of recurrence. Antimicrobial prophylaxis was not associated with decreased risk of recurrent UTI (HR, 1.01; 95% CI, 0.50-2.02), even after adjusting for propensity to receive prophylaxis, but was a risk factor for antibimicrobial resistance among children with recurrent UTI (HR, 7.50; 95% CI, 1.60-35.17).
  
  
  CONCLUSIONS
  Among the children in this study, antimicrobial prophylaxis was not associated with decreased risk of recurrent UTI, but was associated with increased risk of resistant infections.
authors.affiliation: Robert Wood Johnson Clinical Scholars Program, University of Pennsylvania, Philadelphia, PA 19104, USA. pconway2@mail.med.upenn.edu
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Conway
authors.forename: Avital
authors.initials: A
authors.lastname: Cnaan
authors.forename: Theoklis
authors.initials: T
authors.lastname: Zaoutis
authors.forename: Brandon V
authors.initials: BV
authors.lastname: Henry
authors.forename: Robert W
authors.initials: RW
authors.lastname: Grundmeier
authors.forename: Ron
authors.initials: R
authors.lastname: Keren
mesh_terms: D019072:Antibiotic Prophylaxis; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012008:Recurrence; D012307:Risk Factors; D013997:Time Factors; D014552:Urinary Tract Infections / Q000453:epidemiology* / Q000517:prevention & control*