title: Severity assessment for lower respiratory tract infections:  potential use and validity of the CRB-65 in primary care.
abstract: OBJECTIVE
  To explore the potential use of the CRB-65 rule (based on Confusion, Respiratory rate, Blood pressure and age >65 years) in adults  with lower respiratory tract infection (LRTI) in primary care.
  
  
  METHODS
  Primary care clinicians in 13 European countries recorded antibiotic treatment and clinical features for adults with LRTI. Patients  recorded daily symptoms. Multilevel regression models determined the association between an elevated CRB-65 score and prolonged  moderately severe symptoms, hospitalisation, and time to recovery. Sensitivity analyses used zero imputation.
  
  
  RESULTS
  Respiratory rate and blood pressure were recorded in 22.7% and 31.9% of patients, respectively. A total of 2,690 patients  completed symptom diaries. The CRB-65 could be calculated for 339 (12.6%). A score of >1 was not significantly associated with  prolonged moderately severe symptoms (odds ratio (OR) 0.42, 95% CI 0.04 to 4.19) or hospitalisations (OR 3.12, 95% CI 0.16 to 60.24),  but was associated with prolonged time to self-reported recovery when using zero imputation (hazard ratio (HR) 0.75, 95% CI 0.64 to  0.88).
  
  
  CONCLUSIONS
  Respiratory rate and blood pressure are infrequently measured in adults with LRTI. We found no evidence to support using  the CRB-65 rule in the assessment of LRTI in primary care. However, it is unclear whether it is of value if used only in patients where the  primary care clinician suspects pneumonia.
authors.affiliation: Department of Primary Care and Public Health, School of Medicine, Cardiff University, Cardiff, UK. francisna@cf.ac.uk
authors.forename: Nick A
authors.initials: NA
authors.lastname: Francis
authors.forename: Jochen W
authors.initials: JW
authors.lastname: Cals
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Butler
authors.forename: Kerenza
authors.initials: K
authors.lastname: Hood
authors.forename: Theo
authors.initials: T
authors.lastname: Verheij
authors.forename: Paul
authors.initials: P
authors.lastname: Little
authors.forename: Herman
authors.initials: H
authors.lastname: Goossens
authors.forename: Samuel
authors.initials: S
authors.lastname: Coenen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D003221:Confusion; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000175:diagnosis*; D011320:Primary Health Care / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D056152:Respiratory Rate; D012141:Respiratory Tract Infections / Q000145:classification / Q000175:diagnosis*; D012720:Severity of Illness Index