Quality assessment of included studies.

(1) End points: A, Endpoints appropriate to the aim of the study; B, no description about endpoints; C, endpoints inappropriate to the aim of the study. (2) Follow-up period: A, follow-up appropriate to the aim of the study; B, follow-up was not mentioned; C, follow-up in appropriate to the aim of the study. (3) Loss to follow-up: A, loss to follow-up less than 5%; B, no description about the loss; C, loss to follow-up over than 5%; (4) Control group: A, an adequate control group; B, no description about control group; (5) Contemporary groups: A, control and studied groups were managed during the same time period; B, no description about the time period of groups; C, control and studied groups were historical comparison. (6) Baseline of groups: A, groups were similar regarding the criteria other than the studied endpoints (like age, sex); B, no description about the baselines; C, baseline unequal among groups. (7) Statistical analyses: A, adequate statistical analyses; B, inadequate statistical analyses.