Osteoporosis and venous thromboembolism: a retrospective cohort study in the UK General Practice Research Database

In a retrospective cohort study using the General Practice Research Database (GPRD), there was a greater association of venous thromboembolism (VTE) in osteoporotic than in non-osteoporotic female patients. No greater association was shown in treated patients with strontium ranelate or alendronate compared to untreated osteoporotic female patients. We explored the risk of VTE in usual practice in osteoporotic and non-osteoporotic women with and without anti-osteoporotic treatment. A retrospective study was conducted using the GPRD in the UK. The cohorts consisted of untreated osteoporotic women (N = 11,546), osteoporotic women treated with alendronate (N = 20,084), or strontium ranelate (N = 2,408), and a sample of non-osteoporotic women (N = 115,009). Cohorts were compared using a Cox proportional hazards regression model. There was a significantly increased relative risk for VTE in untreated osteoporotic women versus non-osteoporotic women (annual incidence 5.6 and 3.2 per 1,000 patient-years, respectively; relative risk 1.75 [95% confidence interval (CI), 1.09-1.84]). Results were confirmed using adjusted models. The annual incidences of VTE in osteoporotic patients treated with strontium ranelate and alendronate were 7.0 and 7.2 per 1,000 patient-years, respectively, with no significant difference between untreated and treated patients whatever the treatment. Adjusted hazard ratios for treated versus untreated osteoporotic women were 1.09 (95% CI, 0.60-2.01) for strontium ranelate and 0.92 (95% CI, 0.63-1.33) for alendronate. This study shows a greater association of VTE in osteoporotic compared to non-osteoporotic patients, but does not show any greater association in treated patients with strontium ranelate or alendronate compared to untreated osteoporotic patients.