Fig. 6

a Hazard ratios for all-cause mortality after propensity score matching determined using Cox proportional hazard regression. a The type I group against the type IV group (reference); b the type II group against the type IV group (reference); c the type III group against the type IV group (reference); d the type V group against the type IV group (reference). *P < 0.05, **P < 0.0001 versus the type IV group. Error bars correspond to 95% confidence intervals