Association of Delirium with Long-Term Mortality in Critically Ill Patients with COPD Who Survived to Discharge: A Retrospective Cohort Study

Critically ill patients with chronic obstructive pulmonary disease (COPD) face significant mortality after hospital discharge. Delirium is common in patients with COPD, but its impact on long-term mortality in critically ill COPD patients who survive to discharge remains uncertain.

Critically ill patients with COPD who survived to discharge were selected from the Medical Information Mart for Intensive Care IV database. Delirium was assessed using the Confusion Assessment Method for Intensive Care Unit. The primary outcome was 365- and 180-day mortality after discharge. The secondary outcomes included 90- and 30-day mortality following discharge, length of intensive care unit (ICU) and hospital stays, and nursing care needs after hospital discharge.

Of the 2621 survivors of critically ill COPD patients, 982 had suffered delirium during their ICU stay and 709 died within 365 days after hospital discharge. Delirium was significantly associated with 365-day mortality after hospital discharge (adjusted hazard ratio [HR] 1.22; 95% confidence interval [CI] 1.02–1.47). The results were consistent for 180-, 90-, and 30-day post-discharge mortality (adjusted HR [95% CI]: 1.35 [1.09–1.66], 1.48 [1.16–1.89], and 1.68 [1.21–2.32], respectively). Additionally, patients with delirium had longer ICU and hospital stay (adjusted β 2.75; 95% CI 2.35–3.16 and 4.25; 95% CI 3.51–4.98, respectively) and increased nursing care needs after hospital discharge (adjusted odds ratio, 1.56; 95% CI 1.13–2.14).

ICU delirium was an independent risk factor for both long-term and short-term mortality in critically ill patients with COPD who survived to discharge.