In-hospital and one-year mortality and their predictors in patients hospitalized for first-ever chronic obstructive pulmonary disease exacerbations: A nationwide population-based study

Abstract

Introduction: Natural history of chronic obstructive pulmonary disease (COPD) is punctuated by exacerbations; however, little is known about prognosis of the firstever COPD exacerbation and variables predicting its outcomes. Materials and Methods: A population-based cohort study among COPD patients with their first-ever exacerbations requiring hospitalizations was conducted. Main outcomes were in-hospital mortality and one-year mortality after discharge. Demographics, comorbidities, medications and in-hospital events were obtained to explore outcome predictors. Results: The cohort comprised 4204 hospitalized COPD patients, of whom 175 (4%) died during the hospitalization. In-hospital mortality was related to higher age (odds ratio [OR]: 1.05 per year; 95% confidence interval [CI]: 1.03-1.06) and Charlson comorbidity index score (OR: 1.08 per point; 95% CI: 1.01-1.15); angiotensin II receptor blockers (OR: 0.61; 95% CI: 0.38-0.98) and b blockers (OR: 0.63; 95% CI: 0.41-0.95) conferred a survival benefit. At one year after discharge, 22% (871/4029) of hospital survivors were dead. On multivariate Cox regression analysis, age and Charlson comorbidity index remained independent predictors of one-year mortality. Longer hospital stay (hazard ratio [HR] 1.01 per day; 95% CI: 1.01-1.01) and ICU admission (HR: 1.33; 95% CI: 1.03-1.73) during the hospitalization were associated with higher mortality risks. Prescription of b blockers (HR: 0.79; 95% CI: 0.67-0.93) and statins (HR: 0.66; 95% CI: 0.47-0.91) on hospital discharge were protective against one-year mortality. Conclusions: Even the first-ever severe COPD exacerbation signifies poor prognosis in COPD patients. Comorbidities play a crucial role in determining outcomes and should be carefully assessed. Angiotensin II receptor blockers, b blockers and statins may, in theory, have dual cardiopulmonary protective properties and probably alter prognosis of COPD patients. Nevertheless, the limitations inherent to a claims database study, such as the diagnostic accuracy of COPD and its exacerbation, should be born in mind.