Tamoxifen use correlates with increased risk of hip fractures in older women with breast cancer: A case-control study in Taiwan.

AIM: This study aimed to evaluate the association between tamoxifen use and hip fractures in older women with breast cancer in Taiwan.

METHODS: We carried out a retrospective nationwide case-control study using the database of the Taiwan National Health Insurance Program. A total of 762 female patients with breast cancer aged ≥65 years newly diagnosed with hip fractures from 2000 to 2011 were identified for inclusion in the study. Additionally, 7620 female patients with breast cancer aged ≥65 years without hip fractures were randomly selected as controls. Patients were defined as having used tamoxifen if they had an existing prescription for tamoxifen before the index date. Patients were defined as having never used tamoxifen if they had never been given a prescription for tamoxifen before the index date. We used an unconditional logistic regression model to calculate the odds ratio and 95% confidence interval for the association between tamoxifen use and risk of hip fractures.

RESULTS: After adjustment for confounding variables, compared with patients who did not use tamoxifen, the adjusted odds ratio of hip fracture was 2.29 for those who had used tamoxifen (95% confidence interval 1.92, 2.72). Furthermore, adjusted odds ratios were 2.74 (95% confidence interval 2.19, 3.42) among patients with a cumulative duration of tamoxifen use of >3 years.

CONCLUSION: Tamoxifen use is associated with increased risk of hip fractures among older women with breast cancer in Taiwan. Geriatr Gerontol Int 2018; ••: ••-••.