Two influential medical journals have issued expressions of concern about the data used in different coronavirus studies - data that came from the same international registry.
One study, in the Lancet, found that giving hydroxychloroquine or chloroquine to hospitalized coronavirus patients was linked to increased rates of mortality and serious heart rhythm complications, reports the CNN.
"We are issuing an Expression of Concern to alert readers to the fact that serious scientific questions have been brought to our attention," the Lancet editors wrote, noting that "important scientific questions have been raised about data" in the paper.
The Lancet said results of an independent audit to determine the validity of the data in the study, published May 22, were expected "very shortly."
Its study had provided a counterpoint to US President Donald Trump, who has called hydroxychloroquine a "game-changer."
Another study, published in the New England Journal of Medicine on May 1, found that certain heart disease drugs, including ACE inhibitors, didn't worsen the risk of death for coronavirus patients.
"This retrospective study used data drawn from an international database that included electronic health records from 169 hospitals on three continents. Recently, substantive concerns have been raised about the quality of the information in that database. We have asked the authors to provide evidence that the data are reliable," the New England Journal of Medicine editors wrote Tuesday.
Both studies used data from Surgisphere, which describes itself as a "public service organization dedicated to making the world a better place."
"Our multi-national observational registry study published in The Lancet Medical Journal has been met with both high praise and some skepticism from the scientific community and global institutions," Surgisphere said in a statement posted on its website.
"The Surgisphere registry is an aggregation of the deidentified electronic health records of customers of QuartzClinical, Surgisphere's machine learning program and data analytics platform," it added. Surgisphere said it had detected a problem with one hospital in its database. "This hospital was properly reclassified in our database. The findings of the paper are unaffected by this update," it said.
Scientists independent of either study said even if the data mix-up did not affect the conclusions, the discrepancies needed to be cleared up.