In patients receiving treatment with antiosteoporosis medications (AOMs), the risk for venous thromboembolism (VTE) does not differ based on the agent used, according to the results of 2 recent primary care cohort studies (one from the United Kingdom [Clinical Practice Research Datalink; CPRD] and the other from Spain [Base de datos para la investigación Farmacoepidemiológica en Atención Primaria; BIFAP]) published in Osteoporosis International.
The investigators used data from the CPRD and BIFAP primary care records to conduct 2 separate cohort studies. The database study period for CPRD was 2000 to 2014, and the study period for BIFAP was 2001 to 2013. All patients ≥50 years of age with a new prescription or dispensation of an AOM during each database period, along with at least 1 year of available recorded data before treatment initiation, were included in the studies. The study population was divided into 5 exposure cohorts based on AOM of first treatment episode: alendronate, other oral bisphosphonates (etidronate, ibandronante, risedronate, clodronate, and tiludronate, with the last 2 available in Spain only), strontium ranelate, denosumab, and teriparatide.
Incident rate and 95% confidence interval (CI) of each treated VTE per 1000 person-years under initial AOM were estimated according to exposure cohort and age. Hazard ratios and 95% CIs for treated VTE were computed for each exposure cohort compared with alendronate (reference group) via the use of Cox regression. The study populations comprised 159,209 and 83,334 new users of AOMs in CPRD and BIFAP, respectively. The majority of patients were women (80% and 90%, respectively), and alendronate was used by 79.8% and 43.4% of the study cohorts, respectively.
Overall, VTE was detected in 1.28% (2035 of 159,209) of patients from CPRD and 0.48% (401 of 83,334) of patients from BIFAP during the index treatment. Crude incident rates of VTE in the CPRD and BIFAP cohorts, respectively, were as follows: 4.84 (95% CI, 4.61-5.08) and 2.36 (95% CI, 2.04-2.72) per 1000 person-years at risk with alendronate; 5.08 (95% CI, 4.59-5.63) and 2.21 (95% CI, 1.91-2.56) per person-year at risk with other bisphosphonates; 5.06 (95% CI, 3.42-7.48) and 2.89 (95% CI, 2.04-4.09) per person-year at risk with strontium ranelate; 24.06 (95% CI, 3.39-170.8) and 5.16 (95% CI, 0.73-36.60) with denosumab; and 4.67 (95% CI, 2.22-9.79) in BIFAP with teriparatide. Incident rates of VTE increased with age in all the cohorts.
Adjusted hazard ratios for VTE associated with each treatment compared with alendronate in the CPRD and BIFAP cohorts, respectively, were as follows: 1.05 (95% CI, 0.94-1.18) and 0.96 (95% CI, 0.78-1.18) for other bisphosphonates; 0.90 (95% CI, 0.61-1.34) and 1.19 (95% CI, 0.82-1.74) for strontium ranelate; 3.47 (95% CI, 0.49-24.7) and 1.77 (95% CI, 0.25-12.66) for denosumab; and 1.27 (95% CI, 0.59-27.1) for teriparatide in BIFAP only.
The investigators concluded that according to results from the 2 study cohorts, the risk for VTE in patients undergoing treatment for osteoporosis does not differ among the various therapies. Results did not vary with respect to sex, calendar period, or length of risk windows used.
Martín-Merino E, Petersen I, Hawley S, et al. Risk of venous thromboembolism among users of different anti-osteoporosis drugs: a population-based cohort analysis including over 200,000 participants from Spain and the UK [published online December 3, 2017]. Osteoporos Int. doi:10.1007/s00198-017-4308-5