title: The Cape Town Clinical Decision Rule for Streptococcal Pharyngitis in Children.
abstract: Existing clinical decision rules (CDRs) to diagnose group A streptococcal (GAS) pharyngitis have not been validated in sub-Saharan Africa. We developed a locally applicable CDR while evaluating existing CDRs for diagnosing GAS pharyngitis in South African children.
  
  
  
  We conducted a prospective cohort study and enrolled 997 children 3-15 years of age presenting to primary care clinics with a complaint of sore throat, and whose parents provided consent. Main outcome measures were signs and symptoms of pharyngitis and a positive GAS culture from a throat swab. Bivariate and multivariate analyses were used to develop the CDR. In addition, the diagnostic effectiveness of 6 existing rules for predicting a positive culture in our cohort was assessed.
  
  
  
  A total of 206 of 982 children (21%) had a positive GAS culture. Tonsillar swelling, tonsillar exudates, tender or enlarged anterior cervical lymph nodes, absence of cough and absence of rhinorrhea were associated with positive cultures in bivariate and multivariate analyses. Four variables (tonsillar swelling and one of tonsillar exudate, no rhinorrhea, no cough), when used in a cumulative score, showed 83.7% sensitivity and 32.2% specificity for GAS pharyngitis. Of existing rules tested, the rule by McIsaac et al had the highest positive predictive value (28%), but missed 49% of the culture-positive children who should have been treated.
  
  
  
  The new 4-variable CDR for GAS pharyngitis (ie, tonsillar swelling and one of tonsillar exudate, no rhinorrhea, no cough) outperformed existing rules for GAS pharyngitis diagnosis in children with symptomatic sore throat in Cape Town.
authors.affiliation: From the *Department of Medicine, Groote Schuur Hospital and University of Cape Town; and †Division of Clinical Pharmacology, Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa; ‡Division of Medical Microbiology, Department of Pathology, Faculty of Medicine & Health Sciences, Stellenbosch University & NHLS Tygerberg, Tygerberg, South Africa; §College of Public Health & Health Informatics, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia; and ¶Division of Infectious Diseases, Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Engel
authors.forename: Karen
authors.initials: K
authors.lastname: Cohen
authors.forename: Ronald
authors.initials: R
authors.lastname: Gounden
authors.forename: Andre P
authors.initials: AP
authors.lastname: Kengne
authors.forename: Dylan Dominic
authors.initials: DD
authors.lastname: Barth
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Whitelaw
authors.forename: Veronica
authors.initials: V
authors.lastname: Francis
authors.forename: Motasim
authors.initials: M
authors.lastname: Badri
authors.forename: Annemie
authors.initials: A
authors.lastname: Stewart
authors.forename: James B
authors.initials: JB
authors.lastname: Dale
authors.forename: Bongani M
authors.initials: BM
authors.lastname: Mayosi
authors.forename: Gary
authors.initials: G
authors.lastname: Maartens
mesh_terms: D002648:Child; D020000:Decision Support Systems, Clinical; D005260:Female; D006801:Humans; D008297:Male; D010612:Pharyngitis / Q000175:diagnosis* / Q000382:microbiology; D011446:Prospective Studies; D012720:Severity of Illness Index; D013019:South Africa; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D013297:Streptococcus pyogenes