For chronic medical conditions, researchers may considerably exaggerate the results of over one-third of early clinical trials, according to a study published in Mayo Clinic Proceedings.
The study authors examined 70 articles published in medical journals between 2007 and 2015, which included the results of 930 clinical trials.
"This phenomenon of exaggerated early results was present in a whopping 37 percent of the studies we reviewed," said Fares Alahdab, MD, lead study author. "Physicians and patients should be cautious about new or early clinical trial evidence. Exaggerated results could lead to false hope as well as possibly harmful effects."
The research team analyzed clinical trials that evaluated drugs or devices used to treat chronic conditions, including cancer, stroke, heart disease, kidney disease and diabetes. The first or second studies, according to publication year, reported an effect 2.67 times larger than the results of subsequent published trials.
"Often, patients are living with more than one chronic condition, and they and their doctors watch for research about new treatments," said M. Hassan Murad, MD, who led the research team. "They need to be aware that the effect seen in earlier trials may not bear out over time and may be much more modest."