OBJECTIVES: To study the trend of authorship in systematic reviews and meta-analysis (SRMA).

METHODS: This was a cross-sectional review of SRMA published in PubMed (MEDLINE) indexed journals over the past 20 years (1999-2018). List of SRMA published from 1999-2018 was pulled from PubMed using keywords “systematic reviews” and “meta-analysis” (limited to humans, English language and SRMA [publication type]), which retrieved 151207 (08 June 2019) articles. Data was collected to note the number of articles published in each year and number of authors listed. For consistency, date of publication was considered when the issue was allocated and not the date of Epub.

RESULTS: Of the total 151207 articles, 8747 (5.78%), 17918 (11.85%), 41901 (27.71%) and 82641 (54.65%) articles were published in 1999-2003, 2004-2008, 2009-2013 and 2014-2018, respectively. Number of articles in a year ranged from 886 (1999) to 18361 (2017). The majority of articles (n=95744, 63.32%) had 1-5 authors followed by 6-10 (n=46378, 30.67%), 11-15 (n=5743, 3.80%), 21 or more (n=1944, 1.29%) and 16-20 (n=1398, 0.92%). Overall, the number of authors in each article have increased over last 20 years. Articles with 1-5 authors has decreased from 84% (1999) to 55% (2018); however, articles with 6-10 and 11-15 authors has increased from 13.54% to 37.66% and 1.47% to 4.81%, respectively. Of the total articles (n=1944) with 21 or more authors, 1172 (60.29%) articles were published from 2014-2018.

CONCLUSIONS: These results showed that there is a significant increase in number of SRMA and the number of authors to each SRMA in the last 20 years. A major limitation of this analysis was the inclusion of SRMA published in journals indexed in PubMed only; however, the volume of SRMA could be even higher considering SRMA presented at various conferences (but unpublished) or published in journals not indexed in PubMed.