Duration of anticholinergic burden and polypharmacy and the risk of fractures in older Korean adults: a nationwide cohort study

BACKGROUND: Older adults are at elevated risk of fractures and frequently use multiple medications. Evidence on the association between fracture risk, medication use duration, and anticholinergic burden remains limited. This study aimed to examine the association between medication number, anticholinergic burden, and fracture risk in older Korean adults, with additional focus on the role of medication duration. METHODS: Data were obtained from the Korean National Health Insurance Service Senior Database. This study included 32,771 individuals aged 66 years who underwent the National Screening Program for Transitional Ages between 2007 and 2008. Participants were followed for up to 5 years. Multivariate logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of anticholinergic burden and polypharmacy with any fracture, vertebral fractures, and hip fractures. RESULTS: The prevalence of any, vertebral, and hip fractures was 7.0%, 4.6%, and 0.6%, respectively. Fracture prevalence rose with higher anticholinergic burden scores, greater medication numbers, and longer anticholinergic use duration and polypharmacy. The odds of any fracture were higher among those with anticholinergic burden ≥ 3 (OR, 1.17; 95% CI: 1.01–1.36) and those with anticholinergic use ≥ 183 days (OR, 1.45; 95% CI: 1.25–1.69). Risk increased further in participants with anticholinergic burden scores of 1–2 or 2–4 medications combined with ≥ 183 days of use. CONCLUSIONS: Long-term medication use, even with modest anticholinergic burden and few medications, significantly increases fracture risk in older adults. Clinicians should reduce both medication duration and the number of medications to mitigate fracture risk in this population.