Benzodiazepines and the risk of falls in nursing home residents

CONTEXT: For nursing home residents who require a benzodiazepine, short-acting agents are recommended, primarily to avoid increased risk of falls and other injuries associated with the long-acting agents. However, much of the data for the clinical outcomes of falls and injuries comes from community-dwelling older people. OBJECTIVE: To quantify the rate of falls among nursing home residents taking benzodiazepines and how this varies with drug elimination half-life. DESIGN: Historical cohort study. POPULATION: A total of 2510 residents of 53 Tennessee nursing homes, classified according to benzodiazepine use on each day of follow-up. OUTCOME MEASURES: Falls occurring during study follow-up. RESULTS: After adjustment for differences in resident characteristics, benzodiazepine users had a 44% increased rate of falls (adjusted rate ratio 1.44 [95% confidence interval, 1.33-1.56]). The adjusted rate ratio increased from 1.30 (1.12-1.52) for a dose equivalent to less than or equal to 2 mg of diazepam, to 2.21 (1.89-2.60, P < .001) for a dose of >8 mg. The rate of falls was greatest in the 7 days after the benzodiazepine was started (rate ratio of 2.96 [2.33-3.75]) but remained elevated (1.30 [1.17-1.44]) after the first 30 days of therapy. Drugs with elimination half-lives of <12, 12-23, and greater than or equal to 24 hours had adjusted rate ratios of 1.15 (0.94-1.40), 1.45 (1.33-1.59), and 1.73 (1.40-2.14), respectively. Users of hypnotics with elimination half-lives <12 hours had an increased rate of falls occurring during the night (adjusted rate ratio 2.82 [2.02-3.94]). CONCLUSIONS: Although the risk of falls among nursing home residents receiving short-acting benzodiazepines is less than that for the long-acting agents, these drugs are associated with a materially increased risk of nocturnal falls.