title: Risk factors for exacerbation in chronic obstructive pulmonary disease: a prospective study.
abstract: BACKGROUND
  Although acute exacerbations are key events in the progression of chronic obstructive pulmonary disease (COPD), their frequency and the factors associated with acute exacerbation are not fully known.
  
  
  OBJECTIVE
  To determine the incidence and risk factors of very frequent exacerbations in COPD (⩾3 per year).
  
  
  METHODS
  In a cohort study to analyse acute exacerbation and associated factors in 512 primary care patients during a 2-year follow-up, variables of interest were collected for each patient. Acute exacerbation was defined as an event that required antibiotics and/or systemic steroids (moderate) or hospital admission (severe). Odds ratios (OR) were used to determine factors associated with exacerbation.
  
  
  RESULTS
  Incidence of exacerbation was 61.7% in the first year of follow-up and 63.9% in the second year. During the first year, the factors associated with very frequent exacerbation were previous hospital admission (OR 1.69), dyspnoea (moderate [OR 2.86] and severe-very severe [OR 5.83]) and the Charlson Index (OR 1.19); during the second year, associated factors were female sex (OR 4.17), history of previous hospital admissions (OR 2.90), smoking (smoker/ex-smoker) (OR 2.00) and forced vital capacity (OR 0.98).
  
  
  CONCLUSIONS
  Incidence of exacerbation is high in COPD patients. Previous admission for exacerbation is a strong predictor and can identify patients at risk.
authors.affiliation: Epidemiologia Aplicada, Institut de Recerca Biomèdica de Lleida, calle Alcalde Rovira Roure 2, Lleida 25006, Spain. jmontser@alumni.unav.es.
authors.forename: J
authors.initials: J
authors.lastname: Montserrat-Capdevila
authors.affiliation: Biomedical Research Institute (IRB) of Lleida, Lleida, Spain; Health Department, Public Health Agency of Catalonia, Lleida, Spain; and Faculty of Medicine, University of Lleida, Lleida, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Godoy
authors.affiliation: Lleida Research Support Unit, Primary Care Research Institute (IDIAP), Jordi Gol, Autonomous University of Barcelona, Lleida, Spain; Cardiovascular Department, Epidemiology Unit, University Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: J R
authors.initials: JR
authors.lastname: Marsal
authors.affiliation: Biomedical Research Institute (IRB) of Lleida, Lleida, Spain; Health Department, Public Health Agency of Catalonia, Lleida, Spain; Faculty of Medicine, University of Lleida, Lleida, Spain; Pneumology Unit, University Hospital Arnau de Vilanova, Lleida, Spain; and Biomedical Research Centre Network for Respiratory Diseases (CIBERES), Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Barbé
authors.affiliation: Pharmacy Unit, Catalan Health Service, Lleida, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Galván
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D018450:Disease Progression; D004417:Dyspnea / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects