Risk factors for exacerbation in chronic obstructive pulmonary disease: a prospective study

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). PATIENTS AND 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. SUMMARY 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.