title: The quality of control groups in nonrandomized studies published in the Journal of Hand Surgery.
abstract: OBJECTIVE
  To evaluate control group selection in nonrandomized studies published in the Journal of Hand Surgery American (JHS).
  
  
  METHODS
  We reviewed all papers published in JHS in 2013 to identify studies that used nonrandomized control groups. Data collected included type of study design and control group characteristics. We then appraised studies to determine whether authors discussed confounding and selection bias and how they controlled for confounding.
  
  
  RESULTS
  Thirty-seven nonrandomized studies were published in JHS in 2013. The source of control was either the same institution as the study group, a different institution, a database, or not provided in the manuscript. Twenty-nine (78%) studies statistically compared key characteristics between control and study group. Confounding was controlled with matching, exclusion criteria, or regression analysis. Twenty-two (59%) papers explicitly discussed the threat of confounding and 18 (49%) identified sources of selection bias.
  
  
  CONCLUSIONS
  In our review of nonrandomized studies published in JHS, papers had well-defined controls that were similar to the study group, allowing for reasonable comparisons. However, we identified substantial confounding and bias that were not addressed as explicit limitations, which might lead the reader to overestimate the scientific validity of the data.
  
  
  CONCLUSIONS
  Incorporating a brief discussion of control group selection in scientific manuscripts should help readers interpret the study more appropriately. Authors, reviewers, and editors should strive to address this component of clinical importance.
authors.affiliation: Department of Surgery, Saint Joseph Mercy Hospital, Ann Arbor, MI; Section of Plastic Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI; Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI.
authors.forename: Shepard P
authors.initials: SP
authors.lastname: Johnson
authors.affiliation: Department of Surgery, Saint Joseph Mercy Hospital, Ann Arbor, MI; Section of Plastic Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI; Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI.
authors.forename: Sunitha
authors.initials: S
authors.lastname: Malay
authors.affiliation: Department of Surgery, Saint Joseph Mercy Hospital, Ann Arbor, MI; Section of Plastic Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI; Section of Plastic Surgery, University of Michigan Medical School, Ann Arbor, MI. Electronic address: kecchung@umich.edu.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Chung
mesh_terms: D035061:Control Groups; D006801:Humans; D065228:Non-Randomized Controlled Trials as Topic / Q000592:standards*; D018579:Patient Selection; D011643:Publishing / Q000592:standards; D012107:Research Design / Q000592:standards
keywords: Confounding; control group; hand surgery; nonrandomized studies; selection bias