Less than 6 percent of medical drugs have high-quality evidence to support their benefits, according to a recent study by the University of Oxford.
Cochrane Reviews is a British international charitable organization that has made a name for itself by conducting systematic reviews. Essentially, the organization will look at a large number of studies and analyze them to formulate conclusions about whatever the area of study was, from treatments for cancer to the effects of different vitamins.
These influential reviews are often referenced in national and international health care guidelines, and the organization's work is especially prominent in Europe.
Researchers found that less than half of the drugs approved from 2008 to 2021 had moderate to high-quality evidence, according to the reviews. Further, harms were underreported, with around 37 percent of interventions found with harm and 8.1 percent had significant evidence of harm.
“For a doctor or patient to decide whether to use a treatment, they need to know whether the benefits outweigh the harms. If the harms are inadequately measured, an ‘informed choice’ is not possible.”
According to Howick, the “cut-off” year was 2008, since that was when Cochrane Reviews incorporated a system called grading quality of evidence and strength of recommendations (GRADE) to assess the quality of evidence.
It's a widely adopted tool for grading the quality of evidence and for making recommendations, with over 100 organizations worldwide endorsing GRADE.
Although authors of the Oxford study speculated that the poor findings for drugs backed up by high-quality evidence may be because the sample studies were "unrepresentative" of the population, Howicks argued that it was unlikely given the strictness of Cochrane Reviews.
The authors wrote in the study that the FDA “increasingly accepted less data and more surrogate measures,” including clinical measures that show a correlation but may not necessarily guarantee a relationship.
"Potential harms should be measured with the same rigor as potential benefits," Howick concluded. "The evidence-based medicine community is correct to continue calling for higher-quality research, and also justified in their skepticism that high-quality evidence for medical treatments is common or even improving."