title: Is C-reactive protein testing useful to predict outcome in patients with acute bronchitis?
abstract: BACKGROUND
  A recent clinical trial could not find differences between anti-inflammatory drugs, antibiotics and placebo in shortening the duration of symptoms in acute bronchitis.
  
  
  OBJECTIVE
  To investigate if C-reactive protein (CRP) concentrations at presentation are predictive of symptom resolution in these patients.
  
  
  METHODS
  We performed a secondary analysis of the data from a placebo-controlled, randomized clinical trial carried out in primary care. Patients from 18 to 70 years of age presenting a respiratory tract infection of <1 week of evolution, with cough as the predominant symptom and the presence of discoloured expectoration, were enrolled in the study. On the baseline visit, CRP was determined in capillary blood and a five-item symptom diary was given. Patients were followed up to 30 days. The main outcome measure was the number of days with persistent cough.
  
  
  RESULTS
  A total of 312 subjects fulfilled all the criteria for the efficacy analysis and had undergone the CRP test; of these, 56.4% presented a CRP value <8 mg/l and 76% presented <20 mg/l. There were no significant differences in the median duration of cough: 10 days among patients with CRP concentrations <8 mg/l [95% confidence interval (CI): 8-11 days], 11 days among those with concentrations ranging from 8 to 19 mg/l (95% CI: 8-16) and 11 days in those with CRP >20 mg/l (95% CI: 9-12) (P = 0.337).
  
  
  CONCLUSIONS
  Among patients with uncomplicated acute bronchitis and discoloured sputum, the CRP concentrations at presentation are not helpful for predicting symptom resolution.
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain, LlorC@cardiff.ac.uk.
authors.forename: Carl
authors.initials: C
authors.lastname: Llor
authors.affiliation: Section of Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Oleguer
authors.initials: O
authors.lastname: Plana-Ripoll
authors.affiliation: University Rovira i Virgili, Primary Care Centre Jaume I, Tarragona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Moragas
authors.affiliation: Primary Care Centre Valls Urbà, Valls (Tarragona), Spain and.
authors.forename: Carolina
authors.initials: C
authors.lastname: Bayona
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Morros
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain.
authors.forename: Helena
authors.initials: H
authors.lastname: Pera
authors.affiliation: Servei de Pneumologia, Hospital Universitari Vall d'Hebron, CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Miravitlles
mesh_terms: D000208:Acute Disease; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001991:Bronchitis / Q000097:blood* / Q000382:microbiology; D002097:C-Reactive Protein / Q000032:analysis*; D003116:Color; D003371:Cough / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012141:Respiratory Tract Infections / Q000150:complications*; D013183:Sputum; D013997:Time Factors
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: Acute bronchitis; C-reactive protein; cough; primary care; respiratory tract infection.