Central Nervous System Medication Burden and Risk of Recurrent Serious Falls and Hip Fractures in Veterans Affairs Nursing Home Residents

OBJECTIVES: To examine the association between central nervous system (CNS) medication dosage burden and risk of serious falls, including hip fractures, in individuals with a history of a recent fall. DESIGN: Nested case–control study. SETTING: Veterans Health Administration (VHA) Community Living Centers (CLCs). PARTICIPANTS: CLC residents aged 65 and older with a history of a fall or hip fracture in the year before a CLC admission between July 1, 2005, and June 30, 2009. Each case (n = 316) was matched to four controls (n = 1264) on age, sex, and length of stay. MEASUREMENTS: Outcomes were serious falls identified using International Classification of Diseases, Ninth Revision (ACD-9) or Current Procedural Terminology (CPT) E codes, diagnosis codes, or procedure codes associated with a VHA emergency department visit or hospitalization during the CLC stay. Bar code medication administration data were used to calculate CNS standardized daily doses (SDDs) for opioid and benzodiazepine receptor agonists, some antidepressants, antiepileptics, and antipsychotics received in the 6 days before the outcome date by dividing residents’ actual CNS daily doses by the minimum effective geriatric daily doses and adding the results. Multivariable conditional logistic regression models were used to evaluate the association between total CNS medication dosage burden, categorized as 0, 1 to 2, and 3 or more SDDs, and the outcome of recurrent serious falls. RESULTS: More cases (44.3%) than controls (35.8%) received 3.0 or more CNS SDDs (p = .02). Risk of serious falls was greater in residents with 3.0 or more SDDs than in those with 0 (adjusted odds ratio (aOR)=1.49, 95% confidence interval (CI)=1.03–2.14). Those with 1.0 to 2.9 SDDs had a risk similar to that of those with 0 SDDs (aOR=1.03, 95%CI=0.72–1.48). CONCLUSION: Nursing home residents with a history of a fall or hip fracture receiving 3.0 or more CNS SDDs were more likely to have a recurrent serious fall than those taking no CNS medications. Interventions targeting this vulnerable population may help reduce serious falls.