The impact of delirium on outcomes in acute, non-intubated cardiac patients

Background: Because of progress in cardiovascular management, many critically ill geriatric patients undergo various procedures and intensive cardiovascular care treatments. Although delirium frequently affects geriatric patients post-procedurally and after intensive cardiovascular care, the impact of delirium on acute cardiac patients has not been well understood. The objective of this study was to investigate the impact of delirium on outcomes in acute, non-intubated cardiac patients. Methods: This was a prospective cohort study including non-surgical cardiac patients aged 65 years or older admitted to the intensive care unit or intensive cardiac care unit. We excluded mechanically ventilated patients. Delirium was evaluated using the confusion assessment method for the intensive care unit. The primary outcome analysed was 60-day mortality. The secondary outcomes analysed were risk and precipitating factors for delirium development. Results: Of 163 patients, 35 (21.5%) developed delirium. Patients with delirium had higher 60-day mortality rates than those without delirium (22.9% versus 3.9%, P<0.001) and spent an average of 10 days longer in the hospital (32 +/- 20 versus 22 +/- 16 days, P=0.002). On the multivariable Cox analysis, delirium was independently associated with 60-day mortality (adjusted hazard ratio 3.91; 95% confidence interval 1.06-17.36; P=0.04), which was also confirmed by the propensity score-matched analysis. Dementia, history of cerebrovascular disease, and higher sequential organ failure assessment score were significantly associated with delirium development. Conclusions: Acute delirium is common and predicts mortality in non-intubated cardiac patients. Cardiac critical care providers should be aware of this neurological condition.