The relationship between frailty and delirium: insights from the 2017 Delirium Day study

Background: although frailty and delirium are among the most frequent and burdensome geriatric syndromes, little is known about their association and impact on short-term mortality.

Objective: to examine, in hospitalized older persons, whether frailty is associated with delirium, and whether these two conditions, alone or in combination, affect these patients' 30-day survival.

Design: observational study nested in the Delirium Day project, with 30-day follow-up.

Setting: acute medical wards (n = 118) and rehabilitation wards (n = 46) in Italy.

Subjects: a total of 2,065 individuals aged 65+ years hospitalized in acute medical (1,484 patients, 71.9%) or rehabilitation (581 patients, 28.1%) wards.

Methods: a 25-item Frailty Index (FI) was created. Delirium was assessed using the 4AT test. Vital status was ascertained at 30 days.

Results: overall, 469 (22.7%) patients experienced delirium on the index day and 82 (4.0%) died during follow-up. After adjustment for potential confounders, each FI score increase of 0.1 significantly increased the odds of delirium (odds ratio, OR: 1.66 [95% CI: 1.45-1.90]), with no difference between the acute (OR: 1.65 [95% CI: 1.41-1.93]) and rehabilitation ward patients (OR: 1.71 [95% CI: 1.27-2.30]). The risk of dying during follow-up also increased significantly for every FI increase of 0.1 in the overall population (OR: 1.65 [95% CI: 1.33-2.05]) and in the acute medical ward patients (OR: 1.61 [95% CI: 1.28-2.04]), but not in the rehabilitation patients. Delirium was not significantly associated with 30-day mortality in either hospital setting.

Conclusions: in hospitalized older patients, frailty is associated with delirium and with an increased risk of short-term mortality.