Association of polypharmacy with fall-related fractures in older Taiwanese people: age- and gender-specific analyses

Objective To elucidate the associations between polypharmacy and age- and gender-specific risks of admission for fall-related fractures. Design Nested case-control study. Setting This analysis was randomly selected from all elderly beneficiaries in 2007-2008, and represents some 30% of the whole older insurers using Taiwan's National Health Insurance Research Database. Participants We identified 5933 cases newly admitted for fall-related fractures during 2007-2008, and 29 665 random controls free from fracture. Primary and secondary outcome measures Polypharmacy was defined as the use of fall-related drugs of four or more categories of medications and prescribed related to fall within a 1-year period. Logistic regression models were employed to estimate the ORs and related 95% CIs. The interaction of polypharmacy with age and sex was assessed separately. Results Compared with those who consumed no category of medication, older people who consumed 1, 2, 3 and >= 4 categories of medications were all at significantly increased odds of developing fall-related fractures, with a significant dose-gradient pattern (beta=0.7953; p for trend < 0.0001). There were significant interactions between polypharmacy and age, but no significant interactions between polypharmacy and gender. The dose-gradient relationship between number of medications category and risk of fall-related fractures was more obvious in women than in men (beta=0.1962 vs beta=0.1873). Additionally, it was most evident in older people aged 75-84 years (beta=0.2338). Conclusions This population-based study in Taiwan confirms the link between polypharmacy and increased risk of fall-related fractures in older people; and highlights that elderly women and older people aged 75-84 years will be the targeted participants for further prevention from fall-related fractures caused by polypharmacy.