This post-hoc analysis of the IDEAL (Incremental Decrease in End Points Through Aggressive Lipid Lowering) trial was designed to assess the comparative treatment efficacy of high-dose atorvastatin and usual-dose simvastatin for the prevention of events subsequent to the first event, using the Wei, Lin, and Weissfeld method.
Time-to-first-event analysis of data is frequently utilized to provide efficacy outcome information in coronary heart disease prevention trials. However, during the course of such long-term trials, a large number of events occur subsequent to the first event, the analysis of which will be precluded by this approach.
The Wei, Lin, and Weissfeld method allows the analysis of repeated occurrence of events of the same type or of entirely different natures. It regards the recurrence times as multivariate event (failure) times, and models the marginal (individual) distribution for each event with the Cox proportional hazards model.
In the IDEAL trial, compared with patients taking simvastatin 20 to 40 mg daily, patients receiving atorvastatin 80 mg daily had their relative risk of a first cardiovascular event reduced by 17% (p < 0.0001), of a second by 24% (p < 0.0001), of a third by 19% (p = 0.035), of a fourth by 24% (p = 0.058), and of a fifth by 28% (p = 0.117).
Our results indicate that intensive statin therapy continues to be more effective than standard statin therapy, even beyond the first event, and suggest that clinicians should not hesitate to prescribe high-dose statin therapy for patients experiencing multiple recurrent cardiovascular events.