Hospitalization outcomes of delirium in patients admitted to acute care hospitals in their last year of life: a population-based retrospective cohort study

Context — Delirium is a highly distressing neurocognitive disorder for patients at the end of life.

Objectives — To compare hospitalization outcomes between patients with and without delirium admitted to acute care hospitals in the last year of life.

Methods — Using linked administrative data from ICES, this population-based retrospective cohort study included adults who died in Ontario between January 1, 2014 and December 31, 2016 and were admitted to an acute care hospital in their last year of life. Delirium was identified via diagnosis codes on the hospitalization discharge record. Outcomes included length of stay, discharge location and in-hospital mortality. We used multivariable generalized estimating equations to compare outcomes between patients with and without delirium.

Results — Of 208,715 decedents, 9.3% experienced delirium in at least one hospitalization in the last year of life. The mean hospitalization length of stay was 13.8 days in patients with delirium (standard deviation 21.1), or 1.80 times longer (95% confidence interval (CI) 1.75-1.84) compared to those without delirium. Among patients discharged alive, patients with delirium were 1.32 times (95% CI 1.27-1.38) more likely to be discharged to another institution rather than discharged home. There was no difference in in-hospital mortality between patients with and without delirium (relative risk 1.01 (0.98-1.05).

Conclusion — In the last year of life, hospitalized patients with recorded delirium experience poorer outcomes, including longer length of stay and increased risk of post-discharge institution use, compared to those without delirium. These outcomes illustrate added burden for patients, their families and the healthcare system, thus highlighting the need for delirium prevention and early detection in addition to informed transitional care decisions.