title: Influence of lung function on course of disease and response to antibiotic therapy in adult primary care patients with acute cough: a post hoc analysis of patients enrolled in a prospective multicentre study.
abstract: BACKGROUND
  In acute cough patients, impaired lung function as present in chronic lung conditions like asthma and chronic obstructive pulmonary disease (COPD) are often thought to negatively influence course of disease, but clear evidence is lacking.
  
  
  OBJECTIVE
  To investigate the influence of lung function abnormalities on course of disease and response to antibiotic therapy in primary care patients with acute cough.
  
  
  METHODS
  A total of 3,104 patients with acute cough (⩽28 days) were included in a prospective observational study with a within-nested trial, of which 2,427 underwent spirometry 28-35 days after inclusion. Influence of the lung function abnormalities fixed obstruction (forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio <0.7) and bronchodilator responsiveness (FEV1 increase of ⩾12% or 200 ml after 400 μg salbutamol) on symptom severity, duration and worsening were evaluated using uni- and multivariable regression models. Antibiotic use was defined as the reported use of antibiotics ⩾5 days in the first week. Interaction terms were calculated to investigate modifying effects of lung function on antibiotic effect.
  
  
  RESULTS
  The only significant association was the effect of severe airway obstruction on symptom severity on days 2-4 (difference=0.31, 95% confidence interval (CI)=0.03-0.60, P=0.03). No evidence of a differential effect of lung function on the effect of antibiotics was found. Prior use of inhaled steroids was associated with a 30% slower resolution of symptoms rated 'moderately bad' or worse (hazard ratio=0.75, 95% CI=0.63-0.90, P=0.00).
  
  
  CONCLUSIONS
  In adult patients with acute cough, lung function abnormalities were neither significantly associated with course of disease nor did they modify the effect of antibiotics.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Nicole
authors.initials: N
authors.lastname: van Erp
authors.affiliation: Primary Care and Population Sciences Division, University of Southampton, Southampton, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Little
authors.affiliation: Primary Care and Population Sciences Division, University of Southampton, Southampton, UK.
authors.forename: Beth
authors.initials: B
authors.lastname: Stuart
authors.affiliation: Primary Care and Population Sciences Division, University of Southampton, Southampton, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Moore
authors.affiliation: Primary Care and Population Sciences Division, University of Southampton, Southampton, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Institute of Primary Care and Public Health School of Medicine, Cardiff University, Cardiff, UK.
authors.forename: Chris C
authors.initials: CC
authors.lastname: Butler
authors.affiliation: Institute of Primary Care and Public Health School of Medicine, Cardiff University, Cardiff, UK.
authors.forename: Kerenza
authors.initials: K
authors.lastname: Hood
authors.affiliation: 1] Laboratory of Medical Microbiology, Vaccine and Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Antwerp, Belgium [2] Centre for General Practice, Vaccine and Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Antwerp, Belgium.
authors.forename: Samuel
authors.initials: S
authors.lastname: Coenen
authors.affiliation: Laboratory of Medical Microbiology, Vaccine and Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Antwerp, Belgium.
authors.forename: Herman
authors.initials: H
authors.lastname: Goossens
authors.affiliation: Laboratory of Medical Microbiology, Vaccine and Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Antwerp, Belgium.
authors.forename: Margareta
authors.initials: M
authors.lastname: Leven
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Theo J M
authors.initials: TJ
authors.lastname: Verheij
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003371:Cough / Q000209:etiology / Q000503:physiopathology; D005541:Forced Expiratory Volume; D008168:Lung / Q000503:physiopathology; D011320:Primary Health Care; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D013147:Spirometry; D014797:Vital Capacity; D016032:Randomized Controlled Trials as Topic
chemical_list: D000900:Anti-Bacterial Agents