Comorbid Heart Disease in Patients with COPD is Associated with Increased Hospitalization and Mortality - A 15-Year Follow-Up

Purpose: The aim of this study was to examine the association of comorbid heart disease, defined as chronic heart failure or ischemic heart disease, on all-cause and cause-specific hospitalization and mortality in patients with COPD over a period of nearly 15 years. Materials and Methods: The cohort study included patients with COPD from primary and secondary care in 2005 with data from questionnaires and medical record reviews. The Swedish Board of Health and Welfare provided hospitalization and mortality data from 2005 through 2019. Cox regression analyses, adjusted for sex, age, educational level, smoking status, BMI, exacerbations, dyspnea score and comorbid diabetes or hypertension, assessed the association of comorbid heart disease with all-cause and cause-specific time to first hospitalization and death. Linear regression analyses, adjusted for the same variables, assessed this association with hospitalization days per year for those patients that had been hospitalized. Results: Of the 1071 patients, 262 (25%) had heart disease at baseline. Cox regression analysis showed a higher risk of hospitalization for patients with heart disease for all-cause (HR (95% CI) 1.55; 1.32-1.82), cardiovascular (2.14; 1.70-2.70) and other causes (1.27; 1.06-1.52). Patients with heart disease also had an increased risk of all-cause (1.77; 1.48-2.12), cardiovascular (3.40; 2.41-4.78) and other (1.50; 1.09-2.06) mortality. Heart disease was significantly associated with more hospitalization days per year of all-cause (regression coefficient 0.37; 95% CI 0.15-0.59), cardiovascular (0.57; 0.27-0.86) and other (0.37; 0.12-0.62) causes. No significant associations were found between heart disease and respiratory causes of hospitalization and death. Conclusion: Comorbid heart disease in patients with COPD is associated with an increased risk for all-cause hospitalization and mortality, mainly due to an increase of hospitalization and death of cardiovascular and other causes, but not because of respiratory disease. This finding advocates the need of a strong clinical focus on primary and secondary prevention of cardiovascular disease in patients with COPD.