Publication and Level of Evidence Trends in The American Journal of Sports Medicine From 1996 to 2011

Abstract

Background: There has been recent increased emphasis on the publication quality and levels of evidence in orthopaedic sports medicine clinical research. The American Journal of Sports Medicine ( AJSM) began publishing levels of evidence in the abstracts of clinical articles in 2005. Purpose: To analyze trends in the characteristics and levels of evidence of articles published in AJSM. Study Design: Meta-analysis. Methods: All articles in AJSM from 1996, 2001, 2006, and 2011 were analyzed. Articles were analyzed for type: clinical original research, basic science, current concepts review, and case report. Clinical articles were assigned a level of evidence from 1 to 4 and categorized as therapeutic, prognostic, diagnostic, or economic. Descriptive information was collected regarding funding, authorship, and study characteristics. Statistics were calculated using χ2 tests. Results: A total of 795 articles were analyzed. From 1996 to 2011, there has been a significant increase in the percentage of level 1 and 2 articles (9.4% to 23.0%; P = .007) and a significant decrease in the percentage of level 3, 4, and 5 articles (55.1% to 45.1%; P = .037). There was a significant increase in the percentage of therapeutic studies (46.8% to 68.6%; P = .004) and a decrease in prognostic studies (36.7% to 22.2%; P = .03). Publishing authors were from 31 countries, notable for a significant increase in the percentage of studies published by authors from outside the United States from 1996 to 2011 (20.3% to 53.0%; P < .001). The percentage of articles reporting a financial conflict of interest significantly increased during this time (26.1% to 42.2%; P = .006). Conclusion: From 1996 to 2011, the proportion of level 1 and 2 evidence studies published in AJSM has increased significantly. There has been an increase in therapeutic studies and a decrease in prognostic studies. There has been an increase in the number of international studies published.