In reading NEJM's article by Poldermans et al (The Effect of Bisoprolol on Perioperative Mortality and Myocardial Infarction in
High-Risk Patients Undergoing Vascular Surgery, December 9, 1999 -- Vol. 341, No. 240), I noticed something that has struck me before in randomized trials.
There were 50-60 patients in each arm of the placebo controlled trial. This was enough patients to show a statistically significant difference in their endpoint (cardiac death and nonfatal MI). BUT, in the characteristics of patients who began the study, more patients in the standard-care group had "limited exercise capacity" (43% vs 27%). Although to me this difference appears "clinically" significant, it did not reach statistical significance because of the relatively small number in each group.
It would seem that forethought should be done in sample size calculations to avoid having a "clinically" important difference between groups.
Has this been discussed somewhere before?
Brent
Brent W. Beasley, M.D.
Assistant Professor
Department of Internal Medicine
University of Kansas School of Medicine--Wichita
1010 N. Kansas
Wichita, KS 67214
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pho: 316-293-2650
fax: 316-293-1878
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