Fracture risk among patients with cancer compared to individuals without cancer: a population-based study

Background Patients with cancer may be at increased risk of osteoporosis and fracture; however, gaps exist in the existing literature and the association between cancer and fracture requires further examination. Methods We conducted a population-based cohort study of Ontario patients with cancer (breast, prostate, lung, gastrointestinal, haematologic) diagnosed between January 2007 to December 2018 and 1:1 matched non-cancer controls. The primary outcome was incident fracture (end of follow-up December 2019). Multivariable Cox regression analysis was used to estimate the relative fracture risk with sensitivity analysis accounting for competing risk of death. Results Among 172,963 cancer patients with non-cancer controls, 70.6% of patients with cancer were <65 years old, 58% were female, and 9375 and 8141 fracture events were observed in the cancer and non-cancer group, respectively (median follow-up 6.5 years). Compared to non-cancer controls, patients with cancer had higher risk of fracture (adjusted HR [aHR] 1.10, 95% CI 1.07–1.14, p < 0.0001), which was also observed for both solid (aHR 1.09, 95% CI 1.05–1.13, p < 0.0001) and haematologic cancers (aHR 1.20, 95% CI 1.10–1.31, p < 0.0001). Sensitivity analysis accounting for competing risk of death did not change these findings. Conclusions Our study indicates that patients with cancer are at modest risk of fractures compared to non-cancer controls.