Use of benzodiazepines and association with falls in older people admitted to hospital: a prospective cohort study.

Background: Hypnosedatives are commonly prescribed for anxiety and sleep problems. Changes in pharmacokinetics and pharmacodynamics of benzodiazepines (BZDs) during ageing may increase their potential to cause adverse outcomes.

Objective: This study aimed to investigate the use of BZDs in acute care settings and explore their association with falls.

Methods: A prospective cohort study was undertaken of patients aged over 70 years consecutively admitted to 11 acute care hospitals in Australia. Data were collected using the interRAI Acute Care assessment tool. Falls were recorded prospectively (in hospital) and retrospectively (in the 90 days prior to admission).

Results: Of 1,412 patients, 146 (10.3 %) were taking BZDs at admission and 155 (11.3 %) at discharge. Incidence rates of in-hospital fallers for users and non-users of BZDs were not statistically different [incidence rate ratio 1.03, 95 % confidence interval (CI) 0.58-1.82]. There was also no significant association between benzodiazepine use at admission and history of falls in the previous 90 days compared with non-users. However, patients on diazepam were significantly more likely to have a history of falls than all other benzodiazepine users (70.8 vs. 36.1 %; p = 0.002), particularly when compared with oxazepam users (70.8 vs. 25.0 %; p < 0.001). Adjusting for confounders, use of diazepam at admission was positively associated with a history of falls compared with all other benzodiazepine users (odds ratio 3.0; 95 % CI 1.1-8.5; p = 0.036).

Conclusions: Different BZDs may vary in their propensity to predispose to falls, with diazepam having the strongest association. The selection of particular BZDs for older patients should be carefully evaluated.