Peter MA Calverley, Kay Tetzlaff, Daniel Dusser, Robert A Wise, Achim Mueller, Norbert Metzdorf, Antonio Anzueto

Exacerbation history is used to grade the risk of COPD exacerbation, but its reliability and relationship to other risk factors and prior therapy is unclear. To examine these interrelationships, we conducted a post hoc analysis of patients in the TIOSPIR trial with ≥2 years' follow-up or who died on treatment. Patients were grouped by their annual exacerbation rate on treatment into nonexacerbators, infrequent, and frequent exacerbators (annual exacerbation rates 0, ≤1, and >1, respectively), and baseline characteristics discriminating among the groups were determined. We used univariate and multivariate analyses to explore the effect of baseline characteristics on risk of exacerbation, hospitalization (severe exacerbation), and death (all causes). Of 13,591 patients, 6,559 (48.3%) were nonexacerbators, 4,568 (33.6%) were infrequent exacerbators, and 2,464 (18.1%) were frequent exacerbators; 45% of patients without exacerbations in the previous year exacerbated on treatment. Multivariate analysis identified baseline pulmonary maintenance medication as a predictive factor of increased exacerbation risk, with inhaled corticosteroid treatment associated with increased exacerbation risk irrespective of exacerbation history. Our data confirm established risk factors for exacerbation, but highlight the limitations of exacerbation history when categorizing patients and the importance of prior treatment when identifying exacerbation risk.