Association between psychomotor activity delirium subtypes and mortality among newly admitted post-acute facility patients

Abstract

Background: Delirium is common among hospitalized elders and may persist for months. Therefore, the adverse impact of delirium on independence often occurs in the post acute care (PAC) setting. The effect of psychomotor subtypes on delirium remains uncertain. The purpose of this study is to examine the association between psychomotor activity delirium subtypes and 1-year mortality among 457 newly admitted delirious PAC patients.

Methods: Patients were screened for delirium on admission to PAC facilities after an acute hospitalization, and patients with "Confusion Assessment Method"-defined delirium were enrolled. Psychomotor activity was assessed using the Memorial Delirium Assessment Scale, and patients were classified as to their delirium subtype (hyperactive, hypoactive, mixed, or normal). One-year mortality data were obtained from the National Death Index. A Kaplan-Meier survival analysis and a proportional hazards analysis using indicator (dummy) variables with normal psychomotor activity as the referent were performed.

Results: The normal psychomotor activity group had the lowest 1-year mortality rate, followed by the hyperactive, mixed, then hypoactive groups in increasing order. Independent of age, gender, comorbidity, dementia, and delirium severity, hypoactive patients were 1.60 (95% confidence interval [CI], 1.09-2.35) times more likely to die during the 1-year follow-up period than were patients with normal psychomotor activity. The hyperactive (hazard ratio = 1.30; 95% CI, 0.73-2.31) and mixed (hazard ratio = 1.25; 95% CI, 0.72-2.17) psychomotor groups had nonsignificant elevated risks relative to the normal psychomotor behavior group.

Conclusions: All three psychomotor disturbance subtypes had an elevated risk of dying during the 1-year follow-up relative to the normal psychomotor group, though the hypoactive group had the highest mortality risk and was the only group with a statistically significantly elevated risk relative to the normal group.