Patients who receive a randomly assigned treatment as part of a randomised controlled trial (RCT) have the same health outcomes as those who receive individualised treatment tailored by their physician, suggests a new study in PLoS Medicine.

The study will be reassuring to those patients and physicians who fear that taking part in an RCT is worse for a patient's health than receiving a treatment based on a physician's personal judgment, according to the authors, led by Cary Gross at Yale University School of Medicine.

The researchers examined previous RCTs that included information on the health outcomes of patients who participated in the trials as well as patients who were eligible to participate but who did not in the end take part. They only considered RCTs where these non-participants had access to exactly the same treatments as those being tested in the RCTs. Unlike the trial participants (who received treatment randomly), these non-participants received individualized treatment recommended by their physician.

The authors found 25 RCTs that met these requirements, involving nearly 18,000 patients. Overall 45% of patients had received a randomly assigned treatment as part of a clinical trial, while 55% of patients did not in the end participate in the trial and received individualised treatment.

Most of the RCTs studied new treatments for cancer, problems of the heart and circulation, and obstetric and gynaecological problems.

The health outcomes recorded in the trials varied and included, for example, death or recurrence of cancer. In 22 of these trials, the health outcomes were no different statistically in patients who received randomly assigned treatment and those who received individualised treatment. In one trial the randomized patients fared better, and in the remaining two trials the patients receiving individualised treatment fared better.

These findings, say the authors, suggest that "randomized treatment allocation as part of an RCT is unlikely to be harmful."

This does not imply, they say, that all research is free of risk, as the risks and benefits of experimental treatment may vary substantially between studies.

"However, in the situation in which patients will have access to the treatments that are used in the study setting regardless of whether the patient enrolls, prospective participants and their referring physicians should be reassured: there is no evidence that random treatment assignment leads to worse clinical outcomes."

A full copy of the article is available here.