Impact of delirium on post-discharge mortality in coronary care unit patients: A retrospective cohort study.

Background: Coronary care unit (CCU) patients surviving to discharge still face significant mortality. Delirium is common in CCU patients and has been associated with poorer CCU and in-hospital outcomes.

Aim: To assess the association between delirium and mortality after hospital discharge in CCU survivors.

Study design: This was a retrospective observational study that included patients admitted to CCU. All data were extracted from the Medical Information Mart for Intensive Care IV database. The exposure was delirium during CCU stay. The primary outcome was mortality 180 days after hospital discharge. Secondary outcomes included post-hospital discharge mortality at 90 days, length of CCU and hospital stays, and hospital discharge disposition.

Results: Of the 3609 CCU patients included, 891 were considered delirium-positive during their CCU stay. Delirium was associated with an increased risk of mortality at 180 days after hospital discharge (adjusted hazard ratio [HR], 1.33; 95% confidence interval (CI), 1.08-1.64). Similar results were observed for 90-day post-discharge mortality (adjusted HR,1.43; 95% CI, 1.13-1.83). CCU patients who experienced delirium had longer stays in both the CCU and hospital (adjusted β, 2.11; 95% CI, 1.79-2.43 and 3.87; 95% CI, 3.06-4.69, respectively). They were also more likely to require nursing care after hospital discharge (adjusted odds ratio [OR], 1.65; 95% CI, 1.22-2.22).

Conclusion: Delirium during CCU stay was associated with an increased risk of all-cause mortality up to 180 days in CCU patients who survived hospital discharge.

Relevance to clinical practice: Delirium places CCU patients at a higher risk of post-discharge mortality and increased health care resource requirements. Given the high prevalence of delirium in CCU patients and its significantly deleterious impact on both short-term and long-term post-discharge mortality, nurses and physicians should enhance the post-discharge management of patients who experience delirium in order to improve prognosis. This also highlights the importance of preventing and managing delirium during hospitalization.