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