Association between Central Nervous System Drugs and Femoral Fracture Risk in Japanese Individuals ≥80 Years Old: A Case-crossover Study

Objectives To assess the association between concomitant use of central nervous system drugs and femoral fracture risk in individuals ≥80 years old in Japan. Methods A case-crossover design was used, defining the case period as 3 days before the fracture diagnosis and the control period as 31-33, 34-36, and 37-39 days prior. The association between the daily intake of central nervous system drugs (Anatomical Therapeutic Chemical codes) and fracture risk was analyzed using conditional logistic regression. Patients Using the Japanese administrative claims database, we examined elderly patients diagnosed with femoral neck fractures between January 1, 2009, and December 31, 2020. Results In 255,875 patients, the concomitant use of central nervous system drugs increased the odds ratios of femoral fracture (3.41[95% confidence interval: 3.27-3.55], 3.69 [3.46-3.91], 3.76 [3.42-4.13], and 4.34 [3.86-4.86] for an intake of >0-1, >1-2, >2-3, and >3 central nervous system drugs, respectively). Conclusions The concomitant use of central nervous system drugs is associated with an increased risk of femoral fractures in individuals ≥80 years old in Japan.