While previous studies have demonstrated the increased mortality risk associated with delirium, little is known about the mortality time course. The objective of this study is to estimate the fraction of a year of life lost associated with delirium at 1-year follow-up.
Hospitalized patients 70 years and older who participated in a previous controlled clinical trial of a delirium prevention intervention at an academic medical center from March 25, 1995, through March 18, 1998, were followed up for 1 year after discharge, and patients who died were identified, along with the date of death. The adjusted number of days survived were estimated using a 2-step regression model approach and compared across patients who developed delirium during hospitalization and those who did not develop delirium.
After adjusting for pertinent covariates (age, sex, functional status, and comorbidity), patients with delirium survived 274 days, compared with 321 days for patients without delirium, representing a difference of 13% of a year (hazard ratio, 1.62; P<.001). Results were confirmed with a separate binomial regression analysis.
Patients who experienced delirium during hospitalization had a 62% increased risk of mortality and lost an average of 13% of a year of life compared with patients without delirium. Although delirium is an acute condition, it is associated with multiple long-term sequelae that extend beyond the hospital setting, including premature mortality.