Is lipid lowering therapy an independent risk factor for venous thromboembolism? A population-based case-control study

Introduction The independent effect of lipid lowering therapy (LLT) on venous thromboembolism (VTE) risk is uncertain. Objective To test statin and non-statin LLT as potential VTE risk factors. Methods Using Rochester Epidemiology Project resources, we identified all Olmsted County, MN residents with objectively diagnosed incident VTE (cases) over the 13-year period, 1988-2000 (n = 1340), and one to two matched controls (n = 1538). We reviewed their complete medical records for baseline characteristics previously identified as independent VTE risk factors, and for statin and non-statin LLT. Using conditional logistic regression, we tested the overall effect of LLT on VTE risk and also separately explored the role of statin versus that of non-statin LLT, adjusting for other baseline characteristics. Results Among cases and controls, 74 and 111 received statin LLT, and 32 and 50 received non-statin LLT, respectively. Univariately, and after individually controlling for other potential VTE risk factors (i.e., BMI, trauma/fracture, leg paresis, hospitalization for surgery or medical illness, nursing home residence, active cancer, central venous catheter, varicose veins, prior superficial vein thrombosis, diabetes, congestive heart failure, angina/myocardial infarction, stroke, peripheral vascular disease, smoking, anticoagulation), LLT was associated with decreased odds of VTE (unadjusted OR = 0.73; p = 0.03). When considered separately, statin and non-statin LLT were each associated with moderate, non-significant lower odds of VTE. After adjusting for angina/myocardial infarction, each was significantly associated with decreased odds of VTE (OR = 0.63, p < 0.01 and OR = 0.61, p = 0.04, respectively). Conclusions LLT is associated with decreased VTE risk after adjusting for known risk factors.