Limitations of randomised controlled trials

EDITOR,—T C B Dehn has commented on the problems of accruing patients into randomised controlled trials, noting the understandable reluctance of patients to enter some trials (“I want the best treatment, doctor”) in which the patient's outcome (for example, time to death) is the main end point and, consequently, the patient is unable to benefit from thestudy directly.1 This raises a fundamental issue concerning the usefulness of randomised controlled trials in reliably identifying new clinical knowledge. Less recognised, but equally important, is inconsistent clinical enthusiasm to offer the …