Large proportion of COVID-19 studies have low-level evidence

(HealthDay)—A large proportion of studies on COVID-19 have a low level of evidence, according to a research letter published online July 27 in JAMA Internal Medicine.

Krishna Pundi, M.D., from the Stanford University School of Medicine in California, and colleagues examined the characteristics and expected strength of evidence of COVID-19 studies registered on ClinicalTrials.gov. A total of 1,551 studies registered as of May 19, 2020, met the inclusion criteria, including 911 interventional (664 randomized clinical trials [RCTs]) and 640 observational studies.

The researchers found that mortality, ventilation requirement, and treatment complications were frequently reported primary and secondary outcomes (33.9, 26.6, and 23.1 percent, respectively). Of the studies, 29.1 percent could potentially yield the highest level of individual study evidence, 2011 Oxford Center for Evidence-Based Medicine level 2 evidence. Blinding was reported for 364 RCTs, of which 29.3, 35.8, and 17.0 percent were placebo-controlled, planned enrollment of more than 100 participants, and reported at least two study centers or sites, respectively. Only 11.3 percent of RCTs were placebo-controlled and blinded with at least two study centers. Overall, 80.8 and 19.2 percent of the observational studies were single-center and multicenter, respectively. Few studies (13.6 percent) were prospective cohort studies that could yield level 2 evidence.

"Even before results are known, most studies likely will not yield meaningful scientific evidence at a time when rapid generation of high-quality knowledge is critical," the authors write.

Several authors disclosed financial ties to the biopharmaceutical and technology industries.