A new study suggests there has been a drop in the extent to which new medical treatments are shown to be significantly more effective than placebos.
The findings, in a study published in the journal Health Affairs, “suggest that medical breakthroughs that offer large benefits above placebo are becoming less common,” said study co-author Mark Olfson, M.D., M.P.H.
“As a result, now may be a good time to emphasize research that compares established treatments with one another.”
Researchers randomly selected and analyzed 315 placebo-controlled trials that were reported in four leading medical journals between 1966 and 2010.
They found that the average effect size, as measured by the odds ratio (which compares the odds of an outcome resulting from the treatment with the odds of that outcome in absence of the treatment) decreased from a peak of 4.51 (1971–80) to 1.36 (2001–2010).
While placebo-controlled studies are considered to be the gold standard for establishing treatment efficacy, the dwindling effect size over the roughly 40-year period supports the view that comparative effectiveness research — that compares treatments already known to be effective — may provide greater value.
“With apparently declining yield from placebo-controlled studies, it makes good sense to place greater emphasis on comparing two or more treatments that are known to be effective, to evaluate whether there are meaningful differences in their tolerability, safety, and costs,” Olfson said.
Source: Columbia University