Orthopedics Research Today is a free monthly online journal that collates and summarizes the latest research about Orthopedics, including details on chronic injuries, muscoskeletal disorders, surgery, reconstruction. | ||||||||
|
How many patients? How many limbs? Analysis of patients or limbs in the orthopaedic literature: a systematic review.Bryant D, Havey TC, Roberts R, Guyatt G Faculty of Health Sciences, The University of Western Ontario, Elborn College Room 1438, London, ON N6G 1H1, Canada. dianne.bryant@uwo.ca BACKGROUND: Clinical studies assessing orthopaedic interventions often include data from two limbs or multiple joints within single individuals. Without appropriate design or statistical approaches to address within-individual correlations, this practice may contribute to false precision and possible bias in estimates of treatment effect. We conducted a systematic review of the orthopaedic literature to determine the frequency of inappropriate inclusion of nonindependent limb or joint observations in clinical studies. METHODS: We identified seven orthopaedic journals with high Science Citation Index impact factors and retrieved all clinical studies for 2003 for any intervention on any limb or joint. RESULTS: We identified 288 clinical studies, 143 of which involved two limbs or multiple joint observations from single individuals. These studies included nineteen randomized clinical trials (13%) fifty-eight two-group cohort studies (41%), and sixty-six one-group cohort studies (46%). Seventy-six (53%) of the 143 studies involved statistical comparisons between patient groups with use of tests of association, and an additional sixty studies (42%) presented estimates of proportions without statistical comparisons. Only sixteen of the seventy-six studies involving statistical comparisons involved the use of any technique or methodological approach to account for multiple, nonindependent observations. A median of approximately 13% of the patients in these studies contributed more than one observation. The median proportion of nonindependent observations to total observations (the unit of analysis) was approximately 23%. CONCLUSIONS: Our findings suggest that a high proportion (42%) of clinical studies in high-impact-factor orthopaedic journals involve the inappropriate use of multiple observations from single individuals, potentially biasing results. Orthopaedic researchers should attend to this issue when reporting results. Published 4 January 2006 in J Bone Joint Surg Am, 88(1): 41-5.
© 2005-2008 Orthopedics Research Today. All Rights Reserved. |
| ||||||
