Abstract 4987: A Formal Comparison of Risk Factors for Coronary Versus Lower Extremity Peripheral Arterial Disease - Are the Risk Factors Truly the Same?
Although, coronary artery disease (CAD) and lower extremity peripheral arterial disease (PAD) share common risk factors, recent data suggest that the relative importance of both traditional and emerging risk factors may differ in these vascular beds. Prior studies have generally considered separate prediction of each outcome and a formal assessment of similarities in risk factor associations has not been previously undertaken. Utilizing competing risks survival analysis, we assessed traditional cardiovascular risk factors and selected novel biomarkers as predictors of incident CAD and PAD in the Women’s Health Study. Significance testing for equality of risk factor associations was performed. Among 27,079 initially healthy middle-aged women free of prior cardiovascular disease, 784 CAD events and 98 PAD events occurred over a median follow-up of 13.3 years. Biomarkers evaluated were high-sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule-1 (sICAM-1), and the total to high density cholesterol ratio (TC:HDL-C). Among clinical risk factors, age, history of hypertension, and history of hyperlipidemia were significantly associated with both CAD and PAD with comparable magnitudes of effect. Marked dissimilarity was noted for the effect of smoking (former smoking: HRCAD1.3 vs. HRPAD 3.1, p=0.004; current smoking: HRCAD 3.1 vs HRPAD13.6, p<0.001). Higher BMI was associated with increased risk for CAD but appeared inversely related to PAD (HRCAD 1.03 vs HRPAD 0.96 per kg/m2;p=0.004). Diabetes had a larger impact on CAD (HRCAD 5.2 vs HRPAD 2.0;p=0.049). All three biomarkers were significantly associated with both outcomes. No statistically significant difference was evident across tertiles of hsCRP (HRCAD 1.2 vs HRPAD 1.4; p=0.31) and TC:HDL-C (HRCAD 1.7 vs HRPAD 1.3; p=0.08). However, sICAM-1 was more strongly associated with PAD than CAD (HRCAD 1.1 vs HRPAD1.9;p=0.005). In this healthy population of women, we found notably different relationships with PAD for several important cardiovascular risk factors. Our data invoke potential site-specific atherogenic mechanisms which may differentiate coronary from peripheral atherosclerosis.