| | An expert commentary by Marc Cohen, MD, FACC
Clinical trials are the foundation of modern medicine, but they vary in their design and in the strength of their results. In this expert commentary, Dr Marc Cohen answers questions on the design and execution of clinical trials. He discusses the different kinds of clinical trials and the advantages and disadvantages of each type. He also describes how decisions are made on such issues as blinding, inclusion and exclusion criteria, sample size, and endpoints. The value of meta-analyses is discussed as well.
Although one large trial may begin to change our thinking, Dr Cohen suggests that it is only when two large, prospective, randomized clinical trials reach similar conclusions that physicians can feel confident about changing their practice.
Dr Cohen is the Chief of the Division of Cardiology and Director of the Cardiology Fellowship at Newark Beth Israel Medical Center in Newark, New Jersey, as well as Professor of Medicine at the Mount Sinai School of Medicine in New York City.
Suggested Reading List
1. Akobeng AK. Understanding measures of treatment effect in clinical trials. Arch Dis Child. 2005;90:54-56.
2. Lader EW, Cannon CP, Ohman EM, Newby LK, Sulmasy DP, Barst RJ, Fair JM, Flather M, Freedman JE, Frye RL, Hand MM, Jesse RL, Van de Werf F, Costa F; American Heart Association. The clinician as investigator: participating in clinical trials in the practice setting: Appendix 2: statistical concepts in study design and analysis. Circulation. 2004;109:e305-e307.
3. Lyman GH, Kuderer NM. The strengths and limitations of meta-analyses based on aggregate data. BMC Med Res Methodol. 2005;5:14.
4. Roberts C, Sibbald B. Understanding controlled trials. Randomising groups of patients. BMJ. 1998;316:1898-1900.
5. Sibbald B, Roland M. Understanding controlled trials. Why are randomised controlled trials important? BMJ. 1998;316:201.
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