Since the outbreak began, researchers have been quick to publish research on the new coronavirus, which is rapidly spreading worldwide. On Tuesday, for the second time in recent days, a group of scientists questioned data used in studies in two leading medical journals.
A group of scientists who asked questions last week about a study in The Lancet on the use of antimalarial drugs in patients with coronavirus now opposed another article on blood pressure medications in the New England Journal of Medicine, which was published by some of them. authors and were based on the same data record.
Moments after his open letter was published online Tuesday morning, the editors of the N.E.J.M. He published an "expression of concern,quot; about the document and said they had asked the authors of the document to provide evidence that the data is reliable.
The Lancet followed later in the day with a statement about its own concerns regarding the malaria drugs document, saying that the editors have commissioned an independent audit of the data.
Both studies were based on an analysis of patient outcomes from a private database run by a company called Surgisphere, which it says has granular information on nearly 100,000 Covid-19 patients from 1,200 hospitals and other health facilities in six continents. Many healthcare data experts say they knew nothing about its existence until recently.
Both articles were published in May a few weeks apart in highly respected medical journals that subject the studies to peer review prior to publication. Both had considerable impact, halting clinical trials of antimalarial drugs worldwide and providing reassurance about the risks of blood pressure medications taken by millions of patients.
But scientists have not seen the large data set that Surgisphere says it has built, and questions about its provenance are mounting in scientific circles.
In the open letter to the authors of the N.E.J.M. article and magazine editor Dr. Eric J. Rubin, more than 100 physicians, researchers, and statisticians. It required more detailed information on the patient data that served as the basis for the study, and asked for independent validation of the work by a third party.
The study was said to analyze 8,910 Covid-19 patients hospitalized as of mid-March at 169 medical centers in Asia, Europe and North America. The authors concluded that cardiovascular disease increased their risk of dying.
But the document also seemed to allay any concerns that people with high blood pressure might have about taking medications called ACE inhibitors: Some people had wondered if the medications were playing a role in exacerbating the disease.
In contrast, patients who took these drugs were more likely to survive than those who were not, the authors said. (Other studies have also reported that Blood pressure medications do not make people more susceptible to coronavirus infection, and they do not increase the risk of more serious illnesses.
In the article published in The Lancet, the authors said they had analyzed data collected from 671 hospitals on six continents that shared granular medical information on nearly 15,000 patients who had received antimalarial drugs and 81,000 who had not, while protecting their identities.
The documents concluded that the use of chloroquine and hydroxychloroquine may have increased the risk of death in these patients.
The first author of both articles is Dr. Mandeep R. Mehra, a cardiovascular specialist and professor at Harvard Medical School. The second author is Dr. Sapan S. Desai, owner and founder of Surgisphere.
On Tuesday morning, Dr. Desai, who vigorously defended both the studies and their database, said that he and his co-authors of The Lancet study have agreed to a voluntary third-party audit conducted in collaboration with the journal.
He also said that he was arranging the terms of a confidentiality agreement that would allow the editors of the N.E.J.M. to see the data they had requested.
Dr. Desai had previously said that his contractual agreements with hospitals prevented him from disclosing patient data at the hospital level, even though they were anonymous. "Surgisphere supports the integrity of our studies and our scientific researchers, clinical partners, and data analysts," it said in a statement.
In their letter to N.E.J.M., critics of the paper wrote: "Serious, and still unanswered, concerns have been raised about the integrity and provenance of this data."
The letter points to "major inconsistencies,quot; between the number of coronavirus cases reported in some countries during the study period and the number of patient outcomes reported by researchers during the same period.
In particular, they said, it is "difficult to reconcile,quot; the UK Surgisphere data with government reports. The document reported 706 hospitalized patients with confirmed Covid-19 in just seven of the 1,257 UK National Health Service hospitals.
However, a high proportion of coronavirus patients hospitalized in the UK were initially in London, and no London district or hospital had more than 100 confirmed cases as of March 16, critics said.
The case study numbers in Turkey "may not be correct," according to the letter. The document reported data on approximately 346 patients with confirmed cases in three Turkish hospitals as of March 15.
But Istanbul University Hospital, one of the largest hospitals in the city, admitted its first Covid-19 patient on March 16, the writers said.
"Most patient data in Turkish hospitals is entered manually on paper, and Turkey does not have a nationwide electronic digital database other than for blood tests and prescriptions," critics added.
"Furthermore, it is highly unlikely that such clinical data has been shared with a US company without recognition."
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Many of the scientists who first expressed concern about the database are involved in clinical trials of chloroquine and hydroxychloroquine, and were forced to pause the studies for safety reviews after the publication of The Lancet study.
James Watson, senior scientist at MORU Tropical Health Network, said his unit had to immediately suspend work in a large randomized clinical trial to see if chloroquine or hydroxychloroquine can protect health workers exposed to the coronavirus from infection.
"I saw very quickly that this document did not withstand much scrutiny," he said. "We begin to ask ourselves, 'Who has been collecting this data and where does it come from? "We were quite surprised to see a global study with only four authors listed and no recognition from anyone else."
The scientists then turned their attention to the document on cardiovascular disease and blood pressure medications that had been published in the N.E.J.M. May 1st. "We immediately thought, 'If there is something wrong with the database, it will affect both posts,'" he said.
David Glidden, professor of biostatistics at the University of California, San Francisco, who reads all of the new publications on Covid-19 antiviral therapies as a member of the clinical guidelines panel at the National Institutes of Health, said the inaccuracy of descriptions immediately surprised. in both roles
There is a frenzy for publishing research, he added: "Medical journals often feel the pressure to be relevant and bring the story to be discussed, and I think they must respond to the urgency of this pandemic, but also uphold its standards, requiring caution. "