title: Level of evidence in hand surgery.
abstract: BACKGROUND
  Few investigations have been done to analyze the level of evidence in journals related to hand surgery, compared to other related research fields. The objective of this study was to assess the level of evidence of the clinical research papers published in the Ibero-american (RICMA), the European (JHSE) and American (JHSA) Journals of Hand Surgery.
  
  
  METHODS
  A total of 932 clinical research papers published between 2005 and 2009 (RICMA 60, JHSE 461, and JHSA 411) were reviewed. Two independent observers classified the level of evidence based on the Oxford International Classification, 5 being the lowest level and 1 the highest level. The observed frequencies of the level of evidence for each journal were compared with the expected frequencies by a chi-square (χ 2) test for categorical variables with a significance level of 0.05.
  
  
  RESULTS
  Inter-observer agreement analysis showed a Kappa of 0.617. Intra-observer agreement analysis presented a Kappa of 0.66 for the observer 1, and a Kappa of 0.751 for the observer 2. More than 80% of the papers in RICMA and JHSE and a 67.6% in the JHSA presented a level of 4. No level 1 or 2 studies were published in RICMA, compared to JHSE (0.9% level 1 and 5.0% level 2) and JHSA (8.3% level 1 and 10% level 2). The percentage of papers with level 3 published in RICMA (16.7%) was higher compared to the JHSE (11.1%) and the JHSA (14.1%). All the results were statistically significant (χ2=63.945; p<0.001).
  
  
  CONCLUSIONS
  The level of evidence in hand surgery is dependent on the type of journal; being the highest level evidence papers those published in the JHSA, followed by the JHSE and finally the RICMA. Knowing the status of the level of evidence published in hand surgery is the starting point to face the challenges of improving the quality of our clinical research.
authors.affiliation: Unit for Hand & Microsurgery, GECOT, Maria del Cristo Ossuna 20, La Laguna, Tenerife, 38204, Spain. titorosales@telefonica.net
authors.forename: Roberto S
authors.initials: RS
authors.lastname: Rosales
authors.forename: Luis
authors.initials: L
authors.lastname: Reboso-Morales
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Martin-Hidalgo
authors.forename: Isabel
authors.initials: I
authors.lastname: Diez de la Lastra-Bosch
mesh_terms: D015706:Bibliometrics; D016009:Chi-Square Distribution; D019317:Evidence-Based Medicine; D006225:Hand / Q000601:surgery*; D006801:Humans; D015588:Observer Variation; D010506:Periodicals as Topic; D015203:Reproducibility of Results; D012107:Research Design