2.7. Statistical Analysis
Continuous variables are presented as either means (± SD) or medians (with interquartile ranges [IQR]) and categorical variables as numbers and percentages (%). Differences in the continuous variables between the 2 groups were assessed by an unpaired t test or Mann-Whitney test. Categorical variables were compared through a Fisher exact test. The estimated event free survival probabilities were calculated using a Kaplan-Meier analysis; log-rank statistics were used for group comparisons. The follow-up period from the last procedure was calculated with the median value and interquartile range. At first, to assess the clinical predictors of VT-free survival and survival from cardiac death, a univariable Cox proportional analysis was performed. Sequentially, variables with a P<0.10 in the univariable analysis were included in the multivariable analysis, and the hazard ratios (HR) and 95% CI were calculated. A P<0.05 was considered statistically significant. All statistical analyses were performed using SAS 9.4 software (SAS Institute, Cary, NC).
Result