Impacts of Comorbid Chronic Obstructive Pulmonary Disease and Congestive Heart Failure on Prognosis of Critically Ill Patients

Background: Comorbid congestive heart failure (CHF) was associated with worse prognosis in patients with chronic obstructive pulmonary disease (COPD), while few studies specially investigated critically ill patients. This study investigated the associations between comorbid COPD with or without CHF and prognosis of patients admitted to intensive care units (ICU). Methods: We conducted a retrospective cohort study in the Medical Information Mart for Intensive Care III database. Adult ICU patients were included and categorized as patients without COPD and CHF, patients with COPD but without CHF, patients with CHF but without COPD, and patients with both COPD and CHF. The study outcomes were 28-day mortality and 90-day mortality after ICU admission. Kaplan-Meier curves were plotted to estimate the survival distributions between groups and multivariable Cox regression analyses were employed to evaluate the associations between comorbid COPD and/or CHF and the study outcomes. Results: A total of 29,589 patients were included with 20,507 patients without COPD and CHF, 1575 patients with COPD, 6190 patients with CHF, and 1317 patients with both COPD and CHF. The highest 28-day mortality rate and 90-day mortality rate were found in patients with both COPD and CHF (15.95% and 25.74%, respectively), while patients with COPD and patients with CHF had similar mortality rates, also observed in Kaplan-Meier curves. Compared with patients without COPD or CHF, comorbid COPD or CHF both significantly increased the risk of 28-day mortality and 90-day mortality, but comorbid COPD and CHF together was associated with the highest risk of mortality (hazard ratio 1.55 (95% confidence interval (CI) 1.33-1.80) and 1.25 (95% CI 1.16-1.35) for 28-day mortality and 90-day mortality, respectively), while no significant interaction between COPD and CHF was found. Conclusion: ICU patients with comorbid COPD or CHF both experienced greater mortalities, while these two risk factors seemed to play an independent role.