Drug Burden Index in Older Adults with Psychiatric Illnesses: A Cross-Sectional Study

BACKGROUND: Medications with anticholinergic and/or sedative properties are commonly used in the management of psychiatric illnesses. The burden of anticholinergic and sedative medication use has been measured by the Drug Burden Index (DBI) score tool. A higher DBI score has been associated with increased risk of falls, bone and hip fractures, and functional and cognitive impairment, among other serious health outcomes, especially in older adults. OBJECTIVES: We aimed to describe the drug burden in older adults with psychiatric illnesses using DBI, determine the factors that are associated with the drug burden measured by DBI, and examine the association between DBI score and Katz for activities of daily living (ADL) index. METHODS: A cross-sectional study was conducted in the psychogeriatric division of an aged-care home. The study sample comprised all inpatients, aged ≥ 65 years, diagnosed with psychiatric illness. The data obtained included demographic characteristics, duration of hospital stay, primary psychiatric diagnosis and comorbidities, functional status using the Katz ADL index, and cognitive status using the Mini-Mental State Examination (MMSE) score. DBI score was calculated for each anticholinergic and sedative medication used. RESULTS: Of the 200 patients eligible for analysis, 106 (53.1%) were females and the mean age was 76 ± 9 years. The most commonly encountered chronic disorders were hypertension 102 (51%) and schizophrenia 94 (47%). The use of drugs with anticholinergic and/or sedative effects was seen in 163 (81.5%) patients; the mean DBI score was 1.25 ± 1. The results of the multinomial logistic regression showed that schizophrenia (odds ratio (OR) = 2.1 (95% confidence interval (CI) 1.57–4.45), p = 0.01), level of dependency (OR = 3.50 (95% CI 1.38–5.70), p = 0.001), and polypharmacy (OR = 2.99 (95% CI 2.15–4.29), p = 0.003) were significantly associated with DBI score ≥ 1 compared to DBI score 0. CONCLUSIONS: The study showed that anticholinergic and sedative medication exposure measured by DBI was associated with higher levels of dependency on the Katz ADL index in a sample of older adults with psychiatric illnesses from an aged-care home.