Can RCTs be Misleading and Biased?

This clearly implies equivalence, and it has been so interpreted by many others, particularly those biased toward catheter based treatment. Of note, the AHA Guideline appears to be based largely on CREST, and did not even consider the findings of the ICSS trial, published in Lancet the same day as the main article reporting CREST.

Although ICSS may also have flaws, it showed, in a large group of only symptomatic patients, that CAS produced significantly more strokes and diffusion weighted MRI defects than did CEA. It is hard to understand why these ICSS results did not have more of an influence on the AHA Guideline.

Although my bias as a CAS enthusiast makes me believe that CAS will ultimately have a major role in the treatment of carotid stenosis patients, that bias is not yet sufficient for me to spin the data and believe we are now there. One has to wonder if bias more intense than mine was involved in the conclusion reached in the AHA Guideline.

Thus, it is apparent that misleading conclusions can be reached in articles reporting RCTs in leading journals. These can be the result of flaws in the RCTs and/or unrecognized author bias. More importantly, the results of even good trials can be further misinterpreted by others to guide practice standards in a way unjustified by the data.

It is important for all to recognize the possible role of bias in these misinterpretations. By recognizing the possible flaws in RCTs and that physicians, like all other people, are influenced by bias, we can exercise the judgment to use RCTs fairly to help us treat individual patients optimally.n

Dr. Frank J. Veith is professor of surgery at New York University Medical Center and professor of surgery and William J. von Liebig Chair in vascular surgery at Case Western Reserve University and The Cleveland Clinic.