title: PRImary care Streptococcal Management (PRISM) study: identifying clinical variables associated with Lancefield group A β-haemolytic streptococci and Lancefield non-Group A streptococcal throat infections from two cohorts of patients presenting with an acute sore throat.
abstract: OBJECTIVE
  To assess the association between features of acute sore throat and the growth of streptococci from culturing a throat swab.
  
  
  METHODS
  Diagnostic cohort.
  
  
  METHODS
  UK general practices.
  
  
  METHODS
  Patients aged 5 or over presenting with an acute sore throat. Patients were recruited for a second cohort (cohort 2, n=517) consecutively after the first (cohort 1, n=606) from similar practices.
  
  
  RESULTS
  Predictors of the presence of Lancefield A/C/G streptococci.
  
  
  RESULTS
  The clinical score developed from cohort 1 had poor discrimination in cohort 2 (bootstrapped estimate of area under the receiver operator characteristic (ROC) curve (0.65), due to the poor validity of the individual items in the second data set. Variables significant in multivariate analysis in both cohorts were rapid attendance (prior duration 3 days or less; multivariate adjusted OR 1.92 cohort, 1.67 cohort 2); fever in the last 24 h (1.69, 2.40); and doctor assessment of severity (severely inflamed pharynx/tonsils (2.28, 2.29)). The absence of coryza or cough and purulent tonsils were significant in univariate analysis in both cohorts and in multivariate analysis in one cohort. A five-item score based on Fever, Purulence, Attend rapidly (3 days or less), severely Inflamed tonsils and No cough or coryza (FeverPAIN) had moderate predictive value (bootstrapped area under the ROC curve 0.73 cohort 1, 0.71 cohort 2) and identified a substantial number of participants at low risk of streptococcal infection (38% in cohort 1, 36% in cohort 2 scored ≤1, associated with a streptococcal percentage of 13% and 18%, respectively). A Centor score of ≤1 identified 23% and 26% of participants with streptococcal percentages of 10% and 28%, respectively.
  
  
  CONCLUSIONS
  Items widely used to help identify streptococcal sore throat may not be the most consistent. A modified clinical scoring system (FeverPAIN) which requires further validation may be clinically helpful in identifying individuals who are unlikely to have major pathogenic streptococci.
authors.affiliation: Primary Care and Population Science Unit, University of Southampton, Southampton, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Little
authors.forename: Michael
authors.initials: M
authors.lastname: Moore
authors.forename: F D R
authors.initials: FD
authors.lastname: Hobbs
authors.forename: David
authors.initials: D
authors.lastname: Mant
authors.forename: Cliodna
authors.initials: C
authors.lastname: McNulty
authors.forename: Ian
authors.initials: I
authors.lastname: Williamson
authors.forename: Edith
authors.initials: E
authors.lastname: Cheng
authors.forename: Beth
authors.initials: B
authors.lastname: Stuart
authors.forename: Joanne
authors.initials: J
authors.lastname: Kelly
authors.forename: Jane
authors.initials: J
authors.lastname: Barnett
authors.forename: Mark
authors.initials: M
authors.lastname: Mullee
keywords: Primary Care