Publication and level of evidence trends in the American Journal of Sports Medicine from 1996 to 2011.
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.


OBJECTIVE
To analyze trends in the characteristics and levels of evidence of articles published in AJSM.


METHODS
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).


CONCLUSIONS
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.
Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA gregory.cvetanovich@gmail.com.
Gregory L
GL
Cvetanovich
Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA.
Yale A
YA
Fillingham
Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA.
Joshua D
JD
Harris
Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA.
Brandon J
BJ
Erickson
Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA.
Nikhil N
NN
Verma
Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA.
Bernard R
BR
Bach
D001319:Authorship; D015706:Bibliometrics; D035843:Biomedical Research / Q000639:trends; D016265:Conflict of Interest; D019317:Evidence-Based Medicine / Q000639:trends*; D006801:Humans; D009985:Orthopedics / Q000639:trends*; D011643:Publishing / Q000639:trends*; D013178:Sports Medicine / Q000639:trends*; D014481:United States
clinical research; level of evidence; sports medicine