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).