Statistical Methods
death
SENSITIVITY, EVENTS, SECONDARY, EVENT
Because this is a secondary analysis of a trial that has already been completed, a power calculation was not undertaken a priori. For illustration, if 40% of participants experience a primary outcome event over the entire duration of follow-up, equating to ≈250 events, the study would have at least 90% power to detect a hazard ratio of 0.65 or at least 80% power to detect a hazard ratio of 0.70, at a significance level of 5%.All analyses were performed on an intention-to-treat basis according to randomized assignment unless otherwise specified. The treatment groups were compared with a Cox proportional hazards model to calculate hazard ratios and 95% CIs. Unadjusted analyses were performed on the primary outcome, with time to first event measured from randomization to the date of death, withdrawal from the trial, or final trial follow-up. Adjusted analyses were also performed to account for variable timing of ICD or CRT implantation from randomization by including implantation as a time-varying covariate. Sensitivity analyses were performed on the primary outcome in the prespecified subgroup of patients who had an ICD or CRT device at randomization or received one within the first 90 days.The 