Statin treatment and risk of recurrent venous thromboembolism: a nationwide cohort study

OBJECTIVES Statins may decrease the risk of primary venous thromboembolism (VTE), that is, deep vein thrombosis (DVT) and pulmonary embolism (PE) but the effect of statins in preventing recurrent VTE is less clear. The aim of this study was therefore to investigate the association between statin therapy and risk of recurrent VTE. DESIGN A prospective cohort study. SETTING All hospitals in Denmark. PARTICIPANTS All patients with a hospital diagnosis of VTE in Denmark during 1997-2009 associated with a warfarin or heparin prescription were identified. MAIN OUTCOME MEASURES Adjusted HR of recurrent hospitalised VTE (ie, fatal or non-fatal DVT or PE) associated with use of statins. RESULTS 44 330 patients with VTE were included in the study. Of these 3914 were receiving statin therapy at baseline. Patients receiving statins were older (68±11 compared to 62±18 years), had more comorbidity and used more medications. The incidence rate for recurrent VTE was 24.4 (95% CI 22.8 to 26.2) per 1000 person-years among statin users and 48.5 (95% CI 47.4 to 49.7) per 1000 person-years among non-statin users. Statin use was associated with a significantly lower risk of a recurrent VTE, adjusted HR 0.74 (95% CI 0.68 to 0.80), compared with no statin use. The association between statin use and risk of recurrent VTE was significantly affected by age. Among younger individuals (≤80 years), statin use was associated with lower risk of recurrent VTE, HR 0.70 (95% CI 0.65 to 0.76) whereas in older individuals (>80 years) statin use was significantly associated with higher risk of recurrent VTE, HR 1.28 (95% CI 1.02 to 1.60), p for interaction=<0.0001. CONCLUSIONS Statin use was associated with a decreased risk of recurrent VTE.