Association of drug burden index with delirium in community-dwelling older adults with dementia: a longitudinal observational study.

BACKGROUND: The Drug Burden Index (DBI) is a validated tool for assessing the dose-dependent cumulative exposure to sedative and anticholinergic medications. However, the increased risk of delirium superimposed dementia (DSD) with high DBI levels has not yet been investigated.

AIM: This study aimed to examine the potential association between DBI scores and delirium in community-dwelling older adults with dementia.

METHOD: A total of 1105 participants with cognitive impairment underwent a comprehensive geriatric assessment. Experienced geriatricians made the final diagnosis of delirium based on DSM-IV-TR and DSM-V. We calculated the DBI as the sum of all sedatives and anticholinergics taken continuously for at least four weeks before admission. Polypharmacy was defined as regular use of five or more medications. We classified the participants as having no exposure (DBI = 0), low exposure (0 < DBI < 1), and high exposure (DBI ≥ 1).

RESULTS: Of the 721 patients with dementia, the mean age was 78.3 ± 6.7 years, and the majority were female (64.4%). In the whole sample, low and high exposures to anticholinergic and sedative medications at admission were 34.1% (n = 246) and 38.1% (n = 275), respectively. Patients in the high-exposure group had higher physical impairment (p = 0.01), higher polypharmacy (p = 0.01), and higher DBI scores (p = 0.01). In the multivariate Cox regression analysis, high exposure to anticholinergic and sedative medications increased the risk of delirium 4.09-fold compared to the no exposure group (HR = 4.09, CI: 1.63-10.27, p = 0.01).

CONCLUSION: High exposure to drugs with sedative and anticholinergic properties was common in community-dwelling older adults. A high DBI was associated with DSD, highlighting the need for an optimal prescription in this vulnerable population.

TRIAL REGISTRATION: The trial was retrospectively registered at ClinicalTrials.gov. Identifier: NCT04973709 Registered on 22 July 2021.