Predictors of Hospitalized Exacerbations and Mortality in Chronic Obstructive Pulmonary Disease

Exacerbations of chronic obstructive pulmonary disease (COPD) carry significant consequences for patients and are responsible for considerable health-care costs-particularly if hospitalization is required. Despite the importance of hospitalized exacerbations, relatively little is known about their determinants. This study aimed to analyze predictors of hospitalized exacerbations and mortality in COPD patients. This was a retrospective population-based cohort study. We selected 900 patients with confirmed COPD aged ≥35 years by simple random sampling among all COPD patients in Cantabria (northern Spain) on December 31, 2011. We defined moderate exacerbations as events that led a care provider to prescribe antibiotics or corticosteroids and severe exacerbations as exacerbations requiring hospital admission. We observed exacerbation frequency over the previous year (2011) and following year (2012). We categorized patients according to COPD severity based on forced expiratory volume in 1 second (Global Initiative for Chronic Obstructive Lung Disease [GOLD] grades 1-4). We estimated the odds ratios (ORs) by logistic regression, adjusting for age, sex, smoking status, COPD severity, and frequent exacerbator phenotype the previous year. Of the patients, 16.4% had ≥1 severe exacerbations, varying from 9.3% in mild GOLD grade 1 to 44% in very severe COPD patients. A history of at least two prior severe exacerbations was positively associated with new severe exacerbations (adjusted OR, 6.73; 95% confidence interval [CI], 3.53-12.83) and mortality (adjusted OR, 7.63; 95%CI, 3.41-17.05). Older age and several comorbidities, such as heart failure and diabetes, were similarly associated. Hospitalized exacerbations occurred with all grades of airflow limitation. A history of severe exacerbations was associated with new hospitalized exacerbations and mortality.