Two influential medical journals retracted separate coronavirus studies Thursday over concerns about the data used in both studies - data that came from the same international registry.

The authors of the studies, one published in The Lancet and another in The New England Journal of Medicine, requested the studies be retracted because independent auditors weren't able to access all the information needed to verify the data. Both studies used data from data analytics company Surgisphere Corporation.

The retracted Lancet study, published May 22, found Covid-19 patients treated with hydroxychloroquine and chloroquine were more likely to die or suffer dangerous side effects.

The study had provided a counterpoint to President Trump, who has called hydroxychloroquine a "game-changer" for Covid-19. Several countries and the World Health Organization paused ongoing studies looking at the efficacy of the drugs based on The Lancet study, although the WHO resumed its study on Wednesday.

Still, other studies have also found Covid-19 patients did not benefit from treatment with hydroxychloroquine, and they may have experienced serious side effects. More studies on hydroxychloroquine for Covid-19 are under way.

Efforts to verify dataset

In their retraction, Drs. Mandeep Mehra, Frank Ruschitzka and Amit Patel wrote that, after concerns were raised about the data and analyses conducted by Surgisphere and its founder, Sapan Desai, a co-author of the study, they launched a third-party peer review with Desai's consent. They aimed to confirm "the completeness of the database, and to replicate the analyses presented in the paper."

"Our independent peer reviewers informed us that Surgisphere would not transfer the full dataset, client contracts, and the full ISO audit report to their servers for analysis as such transfer would violate client agreements and confidentiality requirements. As such, our reviewers were not able to conduct an independent and private peer review and therefore notified us of their withdrawal from the peer-review process," the three researchers wrote.

"Due to this unfortunate development, the authors request that the paper be retracted," they said. "We all entered this collaboration to contribute in good faith and at a time of great need during the COVID-19 pandemic. We deeply apologize to you, the editors, and the journal readership for any embarrassment or inconvenience that this may have caused."

In a statement, The Lancet said it "takes issues of scientific integrity extremely seriously, and there are many outstanding questions about Surgisphere and the data that were allegedly included in this study." It added: "Institutional reviews of Surgisphere's research collaborations are urgently needed."

The second retracted study, published in The New England Journal of Medicine, had found that certain heart disease drugs, including ACE inhibitors, didn't worsen the risk of death for coronavirus patients. The authors included Desai of Surgisphere and Mehra and Patel, who were authors on study in The Lancet, as well as Drs. SreyRam Kuy and Timothy Henry.

"Because all the authors were not granted access to the raw data and the raw data could not be made available to a third-party auditor, we are unable to validate the primary data sources underlying our article," the authors wrote in the retraction.

"We apologize to the editors and to readers of the Journal for the difficulties that this has caused."

Earlier this week, The Lancet and The New England Journal of Medicine issued expressions of concern about Surgisphere data used in the two studies.

In a statement posted on its website after the expressions of concern, Surgisphere said "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.

"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.

CNN reached out to Surgisphere for comment on Thursday.

"While concealing identifiable individual patient data is important, there are other ways to verify the integrity of the data," Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine who was not involved in either study, said about retraction of The Lancet study.

"For example, data providers should be able to confirm that they have provided data with at the very least, the approximate numbers of patients involved. It is correct to retract the paper in these circumstances." (CNN)

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