BMJ 1995;310:1135 (29 April)

Letters

Carotid endarterectomy

Bias may affect outcome of trials

EDITOR,--Roger N Baird and Mark Lambert--and Peter C Rubin in his commentary--draw varying conclusions about the usefulness of carotid endarterectomy in the prevention of stroke.1 None, however, mention the likelihood of bias in assessments of the outcomes of the two quoted trials of the procedure.2 3 No placebo operations were done in the control groups, so the neurologists assessing the outcomes were almost certainly aware of whether each patient had been operated on. It is unfortunate that their preferred outcome measure, severe ipsilateral ischaemic stroke, is so clearly liable to unconscious bias in its assessment; classic cases are easy to diagnose but there are many on the borderline, which could be included or excluded according to the hopes of the clinician. Noseworthy et al document an instance in which such unblinded assessments by neurologists would have led to a false conclusion of benefit from a . . . [Full text of this article]


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Relevant Article

Controversies in Management: Should carotid endarterectomy be purchased? Treatment avoids much morbidity
Roger N Baird
BMJ 1995 310: 316-317. [Extract] [Full Text]

This article has been cited by other articles:

  • Benade, M. M., Warlow, C. P. (2002). Costs and Benefits of Carotid Endarterectomy and Associated Preoperative Arterial Imaging: A Systematic Review of Health Economic Literature. Stroke 33: 629-638 [Abstract] [Full text]  
  • Lambert, M. (1995). Carotid endarterectomy. BMJ 310: 1471-1471 [Full text]  
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