Associations between drug burden index and falls in older people in residential aged care

Abstract

Objectives: To evaluate the association between the Drug Burden Index (DBI), a measure of a person's total exposure to anticholinergic and sedative medications that includes principles of dose-response and maximal effect and is associated with impaired physical function in community-dwelling older people, and falls in residents of residential aged care facilities (RACFs).

Design: Data were drawn from participants in a randomized controlled trial that investigated falls and fractures.

Setting: RACFs in Sydney, Australia.

Participants: Study participants (N=602; 70.9% female) were recruited from 51 RACFs. Mean age was 85.7 ± 6.4, and mean DBI was 0.60 ± 0.66.

Measurements: Medication history was obtained on each participant. Drugs were classified as anticholinergic or sedative and a DBI was calculated. Falls were measured over a 12-month period. Comorbidity, cognitive impairment (Mini-Mental State Examination) and depression (Geriatric Depression Scale) were determined.

Results: There were 998 falls in 330 individuals during a follow-up period of 574.2 person-years, equating to an average rate of 1.74 falls per person-year. The univariate negative binomial regression model for falls showed incidence rate ratios of 1.69 (95% confidence interval (CI)=1.22-2.34) for low DBI (<1) and 2.11 (95% CI=1.47-3.04) for high DBI (≥1) when compared with those who had a DBI of 0. After adjusting for age, sex, history of falling, cognitive impairment, depression, use of a walking aid, comorbidities, polypharmacy, and incontinence, incident rate ratios of 1.61 (95% CI=1.17-2.23) for low DBI and 1.90 (95% CI=1.30-2.78) for high DBI were obtained.

Conclusion: DBI is significantly and independently associated with falls in older people living in RACFs. Interventional studies designed for this population are needed to determine whether reducing DBI, through dose reduction or cessation of anticholinergic and sedative drugs, can prevent falls.