[A systematic evaluation on the quality of Meta-analysis in articles published in National Medical Journal of China from 1998 to 2014].

Objective: To assess qualities on methodologies and reporting on Meta-analysis used in papers being published in National Medical Journal of China.

Methods: Computerized literature searching was performed in Wangfang Medical Online to collect articles that Meta-analysis was used in the National Medical Journal of China since January 1998 until October 2014. Manual retrieval was also conducted.Qualities on methodologies and reporting were evaluated by both Assessment of Multiple Systematic Reviews (AMSTAR) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) scales.

Results: A total of 74 papers were included. The results on the qualities of methodology evaluation in these papers were 3 to 10 (median 7) scores, 10 articles (13.5%) were rated as high, 61 articles (82.4%) as moderate and 3 articles (4.1%) as low. No statistically significant difference existed in each year of AMSTAR score (χ(2) = 10.205, P = 0.423). The titles of AMSTAR scales with a lower coincidence rate were "Was a list of studies (included and excluded) provided?", "Was the conflict of interest stated?", "Was the status of publication (i.e.grey literature) used as an inclusion criterion?" and "Was the likelihood of publication bias assessed?". The results on the qualities of reporting evaluation in these papers were 5.5 to 26 (median 20) scores, 9 articles (12.2%) scored <15 points, 39 articles (52.7%) 15.5-21 points and 26 articles (35.1%) 21.5-27 points. There was statistically significant difference in each year of PRISMA score (F = 4.301, P = 0.000). And the year 2010 was the highest one. The titles of PRISMA scales with a lack of comprehensive reports were "Structured summary", "Objectives of introduction", "Protocol & registration", "Data collection process", "Data items", "Risk of bias in individual studies", "Risk of bias across studies", "Additional analyses", "Study selection","Risk of bias within studies", "Conclusion limitations", "Conclusions" and "Funding support" etc.

Conclusions: Articles of Meta-analysis published in National Medical Journal of China have a high quality so as to provide rationales for clinical decision-making. However, both of qualities on methodology and reports sill call for continual improvements.