The valid results of Meta-analysis on biomedical data, will have an important value to clinical practice and health policy making. To review the validity of meta-analysis results, one should consider the following issues: The coverage ratio of included studies, quality of data, publication bias and its effect, heterogeneity, the correct selection of statistical methods as well as clinical significance and external validity of overall effect size. The results of Meta-analysis will keep on updating as new related studies are located and included.
