Sleep medication use and risk of fractures in breast cancer survivors

PURPOSE: Sleep problems are more common in breast cancer survivors than those without a cancer history. Our goal was to examine the risk of fractures among breast cancers survivors who used prescription sleep aids. METHODS: We conducted a retrospective cohort study of 21,346 adult women diagnosed with stage 0–III breast cancer between 2009 and 2016 and followed them through 2017. We examined person-year rates of fractures by sleep medication use and calculated adjusted hazard ratios (HR) and 95% confidence intervals (CI) with Cox proportional hazards models using time-dependent variables for sleep medications and covariate medications (antidepressants, anti-anxiety medications, and bisphosphonates) adjusted for demographics, comorbidities, and tumor characteristics and cancer treatments. RESULTS: The sleep medication use was common (40%) in breast cancer survivors and was associated with a 33% increased risk of fractures (adjusted HR = 1.33, 95% CI: 1.20–1.49). Further, in a sensitivity analysis based on new use of sleep medication, the fracture risk was even stronger (adjusted HR = 1.44, 95% CI: 1.26–1.64). CONCLUSION: Given the high use of sleep medications and the high risk of fractures in breast cancer survivors, this study suggests that non-pharmacologic management of sleep problems might be considered as alternative therapy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10549-021-06392-4.