Statistical Analysis
angina
EVENT
The sample size was determined by assuming a standard deviation of 6 angina symptom score units; 284 patients would give 80% power with an alpha of 0.05 to detect a difference of 2 angina symptom score units between the PCI and placebo groups, using a 2-sample t-test. Based on prior experience, the study planned to enroll 396 patients to achieve 284 randomized patients. The trial protocol specified that an analysis of covariance of the ordinal angina symptom score would be performed as the primary analysis. The Statistical Working Group prepared a Statistical Analysis Plan (V1.0, 14For the primary end point, if daily symptom data were not available, the last entered value was used as the final follow-up value unless a high category override event occurred. During the COVID-19 pandemic, hospital research visits for exercise stress tests and stress echocardiography were suspended during national restrictions. This did not impact the primary or questionnaire-based end points. A complete case analysis is presented for the primary endpoint. A sensitivity analysis for the treadmill exercise time and stress echocardiography score endpoints using multiple imputation to account for missing data was performed.The primary end point was analyzed by an ordinal analysis of covariance, which uses a cumulative probability model (also called “cumulative link model”) that does not impose distributional assumptions on the outcome.There were no pre-specified plans to adjust for multiplicity. Therefore, the results are reported as point estimates and 95% confidence intervals and the widths of the confidence intervals should not be used in place of a hypothesis test. The blinding index for patients and staff at baseline and follow-up were calculated using published methods.