True event rate analysis
nonfatal stroke, nonfatal myocardial infarction
EVENT, UNSTABLE ANGINA, SECONDARY
Adjudicated event data were compiled for the primary MACE-4 composite and key secondary endpoints (fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, CV mortality, ACM, hospitalization for unstable angina, and hHF) from the intention-to-treat population. To determine whether the hazard rate for each endpoint was constant over time, parametric models utilizing actual event dates were constructed for each endpoint using PROC LIFEREG with DISTRIBUTION = WEIBULL without any independent variables; as part of the model output, Weibull shape parameter was estimated with 95% confidence intervals (CIs). If the 95% CI contained 1, the Weibull model was reduced to an exponential, or constant hazard rate, model. Three further graphical methods were used to evaluate the exponential model fit: (1) plots of the negative log of Kaplan–Meier survival distribution estimate (− log[S(t)]) vs. time, (2) probability plots from fitting the Weibull model, in order to evaluate the Weibull model fit and therefore confirm that Weibull shape parameter can be used to describe the data distribution, and (3) Epanechnikov kernel-smoothed estimate of the hazard rate plotted against time.