Statistical analysis
Continuous variables were presented as mean ± standard deviation or
median (interquartile range). Categorical variables were presented as
frequency and percentage. The difference of continuous variables between
the subgroups was tested by t-test, or Wilcoxon rank sum test. The
difference of categorical variables between the subgroups was tested by
Pearson chi-square test, Fisher’s exact probability test. Survival
analysis using Kaplan-Meier methods associated with log-rank tests was
applied for cardiovascular events. To explore prognostic factors
associated with incidence of cardiovascular events, Cox proportional
hazards regression model was used. All statistical tests are two-tailed
and statistical significance is set at p<0.05, which were
performed using Stata version 14.0 (College Station, TX).