Clinical trial participants fare no better, no worse than othe...( d more than 20000 patients who were tr...),Health

"The bottom line is that the effects of treatments appear most of the time to be similar inside and outside of trials, and participation in trials doesn't appear to be associated with greater risk than getting the same treatment outside of a trial," reports Andrew Oxman, one of the review authors."

The review appears in the January issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

What is new in this review is that the researchers compared outcomes of study participants with those who did not participate in studies but received similar treatments.

In 91 comparisons, the researchers found no statistically significant differences. Ten comparisons showed better outcomes for patients within the trial, and four comparisons showed worse outcomes for them. One important limitation of the review is that the results are based mainly on "cohort comparisons" that fall short of the most rigorous randomized controlled trials, but Vist says patients similar to the controlled trial participants can expect similar outcomes if given the same treatment outside of a trial.

Oxman himself believes that clinical trials frequently may offer the benefit of better care, despite their finding that there usually is no difference in outcomes. "Typically, when you're cared for in a trial, you're cared for according to a protocol and you often get better follow-up than you get in routine practice," he says. "In addition, health care professionals who participate in trials may be more up-to-date and practice more in accordance with best evidence."

According to a December 2004 survey of 1,000 adults conducted by the non-profit Center for Info
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Contact: GE Vist
gev@nhscr.no
Center for the Advancement of Health
23-Jan-2005