Cumulative incidence function curves for AFR, LRR, DM, and overall mortality were constructed using the Kaplan-Meier method, and comparisons between groups were performed using log-rank tests. A Cox proportional hazards model was used to estimate hazard ratios (HRs), and to identify correlations between outcomes and risk variables. All statistical analyses were carried out with SPSS version 18.0 (SPSS Inc., Chicago, IL, USA). P values < 0.05 were considered statistically significant.