title: Efficiency of a clinical prediction model for selective rapid testing in children with pharyngitis: A prospective, multicenter study.
abstract: BACKGROUND
  There is controversy whether physicians can rely on signs and symptoms to select children with pharyngitis who should undergo a rapid antigen detection test (RADT) for group A streptococcus (GAS). Our objective was to evaluate the efficiency of signs and symptoms in selectively testing children with pharyngitis.
  
  
  METHODS
  In this multicenter, prospective, cross-sectional study, French primary care physicians collected clinical data and double throat swabs from 676 consecutive children with pharyngitis; the first swab was used for the RADT and the second was used for a throat culture (reference standard). We developed a logistic regression model combining signs and symptoms with GAS as the outcome. We then derived a model-based selective testing strategy, assuming that children with low and high calculated probability of GAS (<0.12 and >0.85) would be managed without the RADT. Main outcomes and measures were performance of the model (c-index and calibration) and efficiency of the model-based strategy (proportion of participants in whom RADT could be avoided).
  
  
  RESULTS
  Throat culture was positive for GAS in 280 participants (41.4%). Out of 17 candidate signs and symptoms, eight were retained in the prediction model. The model had an optimism-corrected c-index of 0.73; calibration of the model was good. With the model-based strategy, RADT could be avoided in 6.6% of participants (95% confidence interval 4.7% to 8.5%), as compared to a RADT-for-all strategy.
  
  
  CONCLUSIONS
  This study demonstrated that relying on signs and symptoms for selectively testing children with pharyngitis is not efficient. We recommend using a RADT in all children with pharyngitis.
authors.affiliation: Department of General Pediatrics, Necker - Enfants malades hospital, Assistance Publique - Hôpitaux de Paris, Paris Descartes University, Paris, France.|Inserm UMR 1153, Obstetrical, Perinatal and Pediatric Epidemiology Research Team, Research Center for Epidemiology and Biostatistics Sorbonne Paris Cité (CRESS), Paris Descartes University, Paris, France.|Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.
authors.forename: Jérémie F
authors.identifier: http://orcid.org/0000-0003-3572-8985
authors.initials: JF
authors.lastname: Cohen
authors.affiliation: Association Clinique et Thérapeutique Infantile du Val-de-Marne (ACTIV), Saint-Maur-des-Fossés, France.|Department of Microbiology, Centre Hospitalier Intercommunal de Créteil, Créteil, France.|Université Paris Est, IMRB-GRC GEMINI, Créteil, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Cohen
authors.affiliation: Department of Microbiology, Robert-Debré Hospital, Assistance Publique - Hôpitaux de Paris, Paris Diderot University, Sorbonne Paris Cité, Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bidet
authors.affiliation: Association Clinique et Thérapeutique Infantile du Val-de-Marne (ACTIV), Saint-Maur-des-Fossés, France.
authors.forename: Annie
authors.initials: A
authors.lastname: Elbez
authors.affiliation: Association Clinique et Thérapeutique Infantile du Val-de-Marne (ACTIV), Saint-Maur-des-Fossés, France.|Clinical Research Center, Centre Hospitalier Intercommunal de Créteil, Créteil, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Levy
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Bossuyt
authors.affiliation: Department of General Pediatrics, Necker - Enfants malades hospital, Assistance Publique - Hôpitaux de Paris, Paris Descartes University, Paris, France.|Inserm UMR 1153, Obstetrical, Perinatal and Pediatric Epidemiology Research Team, Research Center for Epidemiology and Biostatistics Sorbonne Paris Cité (CRESS), Paris Descartes University, Paris, France.
authors.forename: Martin
authors.initials: M
authors.lastname: Chalumeau
mesh_terms: D002138:Calibration; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D020000:Decision Support Systems, Clinical; D005260:Female; D005602:France; D006801:Humans; D008297:Male; D010612:Pharyngitis / Q000175:diagnosis*; D010614:Pharynx / Q000382:microbiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012044:Regression Analysis; D013290:Streptococcal Infections / Q000175:diagnosis*; D013297:Streptococcus pyogenes