Prognostic Impact of Delirium in Older People With/Without Dementia: A Retrospective Cohort Study in Taiwan.

Abstract

Objectives: To elucidate the hypothetically different interactions between delirium and post-discharge prognostic indicators in elderly hospital inpatients with versus without dementia.

Design: Retrospective cohort study of claims data by Taiwan National Health Insurance beneficiaries between 2002-2013.

Setting: Records of public hospital admissions in the Taiwan National Health Insurance Research database.

Participants: Propensity-score matched subgroups of patients with delirium superimposed on dementia (n = 922) versus dementia alone (n = 922), delirium alone (n = 680) versus neither delirium nor dementia (n = 680).

Measurements: Mortality, emergency department visits, readmissions, and psychotropic drug use, within 30, 180, and 365 days of discharge, were analyzed using multivariate proportional hazards or logistic regression analyses.

Results: Delirium superimposed on dementia was not associated with increased post-discharge mortality, or emergency department visits, but significantly increased the risk of readmissions at 365-day follow-up (adjusted HR, 95% CI: 1.26, 1.01-1.56). However, delirium without dementia was significantly associated with increased post-discharge mortality, emergency department visits and readmissions at 180 days and 365 days (respective adjusted HRs: mortality, 1.63 and 1.79; adjusted ORs: emergency department visits, 1.89 and 1.81; readmissions, 1.47 and 1.53). Delirium in patients both with dementia and without, was associated with six-fold higher likelihood of in-hospital psychotropic drug use, and doubled post-discharge psychotropic drug usage.

Conclusions: The obvious association between in-hospital delirium and worsened long-term prognosis, irrespective of dementia, raises awareness to warrants proactive and multimodal prevention and intervention strategies. Furthermore, the mechanisms about different influence of delirium for patients with/without dementia need to be further explored.