The quality of control groups in nonrandomized studies published in the Journal of Hand Surgery
Shepard P Johnson1, Sunitha Malay1, Kevin C Chung1
1Department 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.
Purpose:
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.
Clinical Relevance:
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.
