Percent patients with a history of a vascular event within five years of study enrollment, stratified by aPL presence (NEG=negative; POS=positive) and PC4d status (NEG=PC4d<10, POS=PC4d≥10). Results are percent patients with events ± 95% confidence interval (CI). Odds ratio (OR) with 95% confidence interval are displayed. *p=0.02, **p<0.0001, ns not significant at α = 0.05. Regression coefficients were compared using the Wald test in a logistic regression model, exponentiated to determine the odds ratio.