BENZODIAZEPINES AND THE RISK OF FALLING LEADING TO FEMUR FRACTURES - DOSAGE MORE IMPORTANT THAN ELIMINATION HALF-LIFE

Background: In the past decade, the use of benzodiazepines has been id entified as a major independent risk factor for accidental falls. Obje ctive: To study the role of dosing, timing, elimination half-life, and type of benzodiazepine in relation to the occurrence of accidental fa lls leading to hospitalization for femur fractures. Methods: A 1:3 age -, sex-, and pharmacy-matched case-control study was performed using d ata from a Dutch record linkage system (PHARMO) (N = 300 000). Cases i ncluded 493 patients (55 years and older), newly admitted to the hospi tal for a femur fracture resulting from an accidental fall (between 19 86 and 1992). Relative risk estimates were calculated using conditiona l logistic regression analyses to control for the potential confound i ng effects of concomitant drug use and presence of a wide range of und erlying diseases. Results: Falls were significantly associated with cu rrent use of benzodiazepines (odds ratio, 1.6; 95% confidence interval , 1.2 to 2.1) and in particular with short half-life benzodiazepines ( odds ratio, 1.5; 95% confidence interval, 1.1 to 2.0), sudden dose inc reases (odds ratio, 3.4; 95% confidence interval, 1.0 to 11.5), and co ncomitant use of several benzodiazepines (odds ratio, 2.5; 95% confide nce interval, 1.3 to 4.9). A strong dose-response relationship (P < .0 001) and dose-response relations among users of either short or long h alf-life benzodiazepines suggests that these increased risks are expla ined primarily by dose. Conclusions: Benzodiazepines are a major, inde pendent risk factor for falls leading to femur fractures, and the incr eased risk is probably explained by prescribing too-high doses to the elderly.