Outpatient medications and hip fractures in the US: a national veterans study.

BACKGROUND: Certain medications have been linked to falls. One of the most severe fall-related injuries in the elderly is a hip fracture.
OBJECTIVE: The objective of this study was to examine the use of medications known to increase fall risk that were prescribed on an outpatient basis to veterans prior to hospital admission for hip fracture.
METHODS: We identified and analysed the use of outpatient fall-related medications in 2212 unique patients with hip fractures admitted in fiscal year 2003 to Veterans Health Administration hospitals compared with that for matched controls (exact match for age and sex) admitted for acute myocardial infarction (MI) or pneumonia. We analysed the medications selected from the three drug categories most often linked with an increased risk for falls. These categories included medications that affected the cardiovascular (CVS), CNS or the musculoskeletal system (MSS). The unit of analysis was the hip fracture linked with outpatient medications in the study group compared with matched control groups of patients with hospitalisations for an acute MI or pneumonia.
RESULTS: Of the 2212 hip-fracture patients, 70% had fall-related medications prior to hospitalisation for hip fracture. The most notable differences in usage were seen in the drug classes antiepileptics/barbiturates, antidepressants (2-fold difference in use of selective serotonin reuptake inhibitors [SSRIs] and tricyclic antidepressants [TCAs]), and antiparkinson's drugs (nearly 4-fold difference between cases and controls). There were also notable differences in usage of antipsychotics (3-fold difference for hip-fracture cases compared with acute MI) and cholinesterase inhibitors (nearly 2-fold difference for hip-fracture cases compared with pneumonia or acute MI). The most notable differences in polypharmacy combinations were CVS and CNS categories with differences of 9.44% (absolute) and 43% (relative) for hip-fracture patients over acute MI, and 4.83% (absolute) and 18% (relative) for hip-fracture patients over pneumonia patients.
CONCLUSIONS: This is the first national Veterans Health Administration hip fracture hospitalisation study that temporally linked outpatient fall-related medications in hip-fracture patients with matched controls. We found that of veterans with hip-fracture hospitalisations, 70% were prescribed outpatient medications from selected major drug categories that may potentially increase fall risk. Moreover, over one-third of hip-fracture patients received concomitant prescriptions of drugs from multiple selected drug categories. Hip-fracture patients, compared with matched controls of acute MI and pneumonia, had the largest pronounced differences in prescribed medications in the antiepileptics, antidepressants, antipsychotics and antiparkinson's drug classes. Although a randomised clinical trial is the 'gold standard' for determining causation issues, exposing patients, particularly the elderly, to the potential risk of injurious falls would raise serious patient safety research approval issues. If the relationship between selected drugs and falls is indeed to some extent causative, future retrospective multivariate analyses could quantify the magnitude of these effects.