title: Empirical validation of guidelines for the management of pharyngitis in children and adults.
abstract: BACKGROUND
  Recent guidelines for management of pharyngitis vary in their recommendations concerning empirical antibiotic treatment and the need for laboratory confirmation of group A streptococcus (GAS).
  
  
  OBJECTIVE
  To assess the impact of guideline recommendations and alternative approaches on identification and treatment of GAS pharyngitis in children and adults.
  
  
  METHODS
  Throat cultures and rapid antigen tests were performed on 787 children and adults aged 3 to 69 years with acute sore throat attending a family medicine clinic in Calgary, Alberta, from September 1999 to August 2002. Recommendations from 2 guidelines (those of the Infectious Diseases Society of America and of the American College of Physicians-American Society of Internal Medicine/American Academy of Family Physicians/US Centers for Disease Control and Prevention) were compared with rapid testing alone, a clinical prediction rule (ie, the modified Centor score), and a criterion standard of treatment for positive throat culture results only.
  
  
  METHODS
  Sensitivity and specificity of each strategy for identifying GAS pharyngitis, total antibiotics recommended, and unnecessary antibiotic prescriptions.
  
  
  RESULTS
  In children, sensitivity for streptococcal infection ranged from 85.8% (133/155; 95% confidence interval [CI], 79.3%-90.0%) for rapid testing to 100% for culturing all. In adults, sensitivity ranged from 76.7% (56/73; 95% CI, 65.4%-85.8%) for rapid testing without culture confirmation of negative results to 100% for culturing all. In children, specificity ranged from 90.3% (270/299; 95% CI, 86.4%-93.4%) for use of modified Centor score and throat culture to 100% for culturing all. In adults, specificity ranged from 43.8% (114/260; 95% CI, 37.7%-50.1%) for empirical treatment based on a modified Centor score of 3 or 4 to 100% for culturing all. Total antibiotic prescriptions were lowest with rapid testing (24.7% [194/787]; 95% CI, 21.7%-27.8%) and highest with empirical treatment of high-risk adults (45.7% [360/787]; 95% CI, 42.2%-49.3%), due to a high rate of unnecessary prescriptions in adults (43.8% [146/333]; 95% CI, 38.4%-49.4%).
  
  
  CONCLUSIONS
  Guideline recommendations for the selective use of throat cultures but antibiotic treatment based only on positive rapid test or throat culture results can reduce unnecessary use of antibiotics for treatment of pharyngitis. However, empirical treatment of adults having a Centor score of 3 or 4 is associated with a high rate of unnecessary antibiotic use. In children, strategies incorporating throat culture or throat culture confirmation of negative rapid antigen test results are highly sensitive and specific. Throat culture of all adults or those selected on the basis of a clinical prediction rule had the highest sensitivity and specificity.
authors.affiliation: Ray D. Wolfe Department of Family Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada. wmcisaac@mtsinai.on.ca
authors.forename: Warren J
authors.initials: WJ
authors.lastname: McIsaac
authors.forename: James D
authors.initials: JD
authors.lastname: Kellner
authors.forename: Peggy
authors.initials: P
authors.lastname: Aufricht
authors.forename: Anita
authors.initials: A
authors.lastname: Vanjaka
authors.forename: Donald E
authors.initials: DE
authors.lastname: Low
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001431:Bacteriological Techniques; D002648:Child; D002675:Child, Preschool; D004363:Drug Utilization; D006801:Humans; D008875:Middle Aged; D010612:Pharyngitis / Q000188:drug therapy* / Q000382:microbiology*; D017410:Practice Guidelines as Topic; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000188:drug therapy*; D013297:Streptococcus pyogenes / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents