Editor's Choice | This Week in BMJ | Press releases

BMJ No 7102 Volume 315 Letters Saturday 26 July 1997 Informed consent Two stage randomisation and consent would overcome many problems Editor, We believe that two stage randomisation procedures potentially provide a solution to the ethical concerns arising from Martin Dennis and colleagues' study evaluating a stroke family care worker.(1, 2) A two stage randomisation procedure requires that all patients give full consent to their particular role in the trial rather than to a hypothetical scenario. In the first stage of randomisation all patients are asked to give consent for follow up. Consent for additional (non-standard) treatment is sought only from a random sample selected to be offered the study intervention. Therefore, patients-whether they are in the control or intervention group-consent to the assessments and treatment that they will actually receive. This contrasts with the usual one stage consent procedure in randomised controlled trials, whereby patients consent to two or more possible forms of care which they may or may not get. When a one stage procedure is used patients randomised to standard care may feel disadvantaged as a result of not receiving the intervention, particularly if it is a new clinical service. A two stage randomisation clearly would be unethical if the control group were receiving non-standard care. In her commentary on the study Sheila McLean argues that patients should consent to the project rather than their role within it. Surely, however, it is more appropriate that they give personal consent to their assessment and treatment in a project and what will be required of them in the study. We believe that this approach, centred on the patient, is consistent with the highest of ethical standards in medical research. D J Stott Professor of geriatric medicine P Langhorne Senior lecturer in geriatric medicine University of Glasgow, Royal Infirmary, Glasgow G4 0SF H Rodgers Senior lecturer in stroke medicine University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU References 1 Dennis M, O'Rourke S, Slattery J, Staniforth T, Warlow C. Evaluation of a stroke family care worker: results of a randomised controlled trial. [With commentaries by S McLean and M Dennis.] BMJ 1997;314:1071-7. (12 April.) 2 Zelen M. A new design for randomised clinical trials. N Engl J Med 1979;300:1243-5. Home | Current issue | Past issues | Classified ads | Career Focus | Feedback Collections | About this site | About the BMJ | BMA | Medline