Warsinger-Martin, Lisa

Objective: To evaluate whether effects of oral hormone therapy (HT) on risks of venous and arterial vascular events differ by baseline statin or aspirin use. Methods: We performed time-to-event analysis using data from the Women’s Health Initiative menopausal HT randomized trials to assess risk of thrombotic events. Women were randomized to oral conjugated equine estrogens (CEEs) alone or placebo among women with prior hysterectomy (n = 10,739), and CEE with medroxyprogesterone acetate (MPA) or placebo among women with an intact uterus (n = 16,608), stratified by baseline personal use of statins and aspirin. We evaluated risk of prespecified, adjudicated thrombotic events, including coronary heart disease, stroke, venous thromboembolism, and/or composite major adverse cardiovascular events, at 2 and 5 years. Results: Baseline statin use (n = 827 in CEE-alone trial; n = 1,115 in CEE+MPA trial) or aspirin use (n = 2,212; n = 3,431) was limited. At 5-year follow-up, coronary heart disease risk for CEE-alone versus placebo was hazard ratio (HR) = 0.81 (95% CI: 0.44-1.49) in statin users, similar to nonusers, HR = 1.07 (95% CI: 0.82-1.40). For CEE+MPA, there was also no difference by statin use, HR = 1.02 (95% CI: 0.55-1.89) and HR = 1.47 (95% CI: 1.13-1.90), respectively. Neither statin nor aspirin exposure significantly modified effects of HT on any arterial or venous thrombotic outcome at 2 or 5 years. Conclusions: In this secondary randomized clinical trial analysis, neither statins nor aspirin significantly modified effects of oral HT on key arterial or venous thrombotic outcomes at 2 or 5 years. Results, however, may be underpowered given low baseline exposure prevalence for both statins and aspirin.

Background Classification of risk of ischemic stroke is important for medical care and public health reasons. Whether addition of biomarkers adds to predictive power of the Framingham Stroke Risk or other traditional risk factors has not been studied in older women. Methods The Hormones and Biomarkers Predicting Stroke Study is a case-control study of blood biomarkers assayed in 972 ischemic stroke cases and 972 controls, nested in the Women's Health Initiative Observational Study of 93 676 postmenopausal women followed for an average of eight-years. We evaluated additive predictive value of two commercially available biomarkers: C-reactive protein and lipoprotein-associated phospholipase A 2 to determine if they added to risk prediction by the Framingham Stroke Risk Score or by traditional risk factors, which included lipids and other variables not included in the Framingham Stroke Risk Score. As measures of additive predictive value, we used the C-statistic, net reclassification improvement, category-less net reclassification improvement, and integrated discrimination improvement index. Results Addition of C-reactive protein to Framingham risk models or additional traditional risk factors overall modestly improved prediction of ischemic stroke and resulted in overall net reclassification improvement of 6·3%, (case net reclassification improvement = 3·9%, control net reclassification improvement = 2·4%). In particular, high-sensitivity C-reactive protein was useful in prediction of cardioembolic strokes (net reclassification improvement = 12·0%; 95% confidence interval 4·3–19·6%) and in strokes occurring in less than three-years (net reclassification improvement = 7·9%, 95% confidence interval 0·8–14·9%). Lipoprotein-associated phospholipase A 2 was useful in risk prediction of large artery strokes (net reclassification improvement = 19·8%, 95% confidence interval 7·4–32·1%) and in early strokes (net reclassification improvement = 5·8%, 95% confidence interval 0·4–11·2%). Conclusions C-reactive protein and lipoprotein-associated phospholipase A 2 can improve prediction of certain subtypes of ischemic stroke in older women, over the Framingham stroke risk model and traditional risk factors, and may help to guide surveillance and treatment of women at risk.