title: A novel approach to evaluating the benefit of post-urinary tract infection renal ultrasonography, using decision curve analysis.
abstract: The benefit of post-urinary tract infection (UTI) sonography to detect clinically significant renal abnormalities remains a subject open to debate. Decision curve analysis (DCA) is a novel method for evaluating the clinical usefulness of diagnostic tests. Our objective was to determine, using DCA, the benefit of post-UTI sonography and of post-UTI sonography with biological markers of inflammation to predict the risk of recurrence of febrile UTI in children aged 2 to 24 months without known uropathy.
  
  
  
  We retrospectively analyzed all children aged 2 to 24 months, without known uropathy, who presented with a first episode of febrile UTI between 2009 and 2012 and followed them for 30 months. We then used DCA to estimate the benefit of post-UTI sonography or post-UTI sonography + biological markers of inflammation for detecting the risk of recurrence.
  
  
  
  A total of 318 children [144 boys (45.3 %) and 174 girls (54.7 %)], with a mean age of 6.9 ± 5.6 months, were identified. Of these, 210 children presented with a significant inflammation [66.2 %; 95 % confidence interval (CI) 61.0-71.4], and 30 (9.4 %; 95 % CI 6.2-12.6) presented with abnormal post-UTI sonographic findings. Eighteen (5.7 %; 95 % CI 3.1-8.2) children presented with recurrent UTI at 30 months.
  
  
  
  There were significantly more recurrences in those children who presented with abnormal sonographic findings than in those who did not (relative risk 7.68; 95 % CI 3.03-19.46). However, taking into account the effect of false-positives and false negatives, the DCA revealed that for threshold probabilities of >30 %, at which patients/doctors are concerned about unnecessary interventions (whether tests or treatments), neither post-UTI sonography nor post-UTI sonography + biological markers of inflammation have sufficient value to improve care.
authors.affiliation: Department of Pediatric Surgery, CHU de La Réunion, Allée des Topazes, 97400, Saint-Denis, Réunion, France. harper_luke@hotmail.com.
authors.forename: Luke
authors.initials: L
authors.lastname: Harper
authors.affiliation: Department of Pediatric Surgery, CHU de La Réunion, Allée des Topazes, 97400, Saint-Denis, Réunion, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Delforge
authors.affiliation: Department of Pediatric Surgery, CHU de La Réunion, Allée des Topazes, 97400, Saint-Denis, Réunion, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Maurin
authors.affiliation: Department of Pediatric Nephrology, CHU de La Réunion, Saint-Denis, Réunion, France.
authors.forename: Valerie
authors.initials: V
authors.lastname: Leroy
authors.affiliation: Department of Pediatric Surgery, CHU de La Réunion, Allée des Topazes, 97400, Saint-Denis, Réunion, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Michel
authors.affiliation: Department of Pediatric Surgery, CHU de La Réunion, Allée des Topazes, 97400, Saint-Denis, Réunion, France.
authors.forename: Frederique
authors.initials: F
authors.lastname: Sauvat
authors.affiliation: Unité de Soutien Méthodologique, CHU de La Réunion, Saint-Denis, Réunion, France.|INSERM, CIC 1410, 97410, Saint Pierre, Réunion, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Ferdynus
mesh_terms: D015415:Biomarkers; D003658:Decision Making, Computer-Assisted; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D007223:Infant; D007249:Inflammation / Q000000981:diagnostic imaging / Q000209:etiology; D008297:Male; D011237:Predictive Value of Tests; D012008:Recurrence; D012189:Retrospective Studies; D014463:Ultrasonography; D014551:Urinary Tract / Q000000981:diagnostic imaging*; D014552:Urinary Tract Infections / Q000150:complications* / Q000000981:diagnostic imaging*
chemical_list: D015415:Biomarkers
keywords: Decision curve analysis; Diagnostic test; Ultrasound; Urinary tract infection