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An early and influential paper on long COVID that appeared in The Lancet has been flagged with an expression of concern while the journal investigates "data errors" brought to light by a reader.
An editorial that accompanied the paper when it was published in January of last year described it as "the first large cohort study with 6-months' follow-up" of people hospitalized with COVID-19. The article has received plenty of attention since then.
Titled "6-month consequences of COVID-19 in patients discharged from hospital: a cohort study," the paper has been cited nearly 1,600 times, according to Clarivate's Web of Science. Altmetric finds references to it in multiple documents from the World Health Organization.
According to the expression of concern, dated November 24, a reader found inconsistencies between the data in the article and a later paper describing the same cohort of patients after a year of follow-up. That discovery sparked an investigation that is still ongoing:
On Jan 8, 2021, The Lancet published an Article, 6-month consequences of COVID-19 in patients discharged from hospital: a cohort study, by Chaolin Huang and colleagues. 1 On Aug 28, 2021, The Lancet published an Article, 1-year outcomes in hospital survivors with COVID-19: a longitudinal cohort study, by Lixue Huang and colleagues. 2 We received an inquiry from a researcher on data inconsistencies between these two Articles, and we sought an explanation from the corresponding author of the two papers. On Nov 7, 2022, Lancet editors were informed that inconsistencies between the 6-month and the 1-year data were due to "some variables in the dataset used for the 6-month paper were mistakenly disrupted in order". In view of the extent of these data errors, we now issue an Expression of Concern about the 6-month paper 1 while we investigate further, including further statistical and clinical review of the corrected data. We will update this notice as soon as we have further information.
The corresponding author of both papers, Bin Cao of China's National Center for Respiratory Medicine and the China-Japan Friendship Hospital in Beijing, has not responded to our request for comment.
A profile of Cao published in Lancet Infectious Diseases last March described him as "a leading researcher in pneumonia and influenza" who "has been instrumental in increasing knowledge about COVID-19." In addition to the follow-up study of hospitalized COVID patients:
Cao's seminal papers during the COVID-19 pandemic include the first report of the clinical characteristics of COVID-19 patients in Wuhan, the description of the risk factors for mortality for adult inpatients, and the results of trials testing the use of antiviral drugs, including lopinavir-ritonavir, to treat COVID-19 in China.
We reached out to The Lancet's press office and Richard Horton, the journal's editor-in-chief, and received this statement:
The Lancet Group treats all communications between editors and authors or readers as confidential. Investigations are continuing, and the Expression of Concern will be updated as soon as we have further information to share. More information about our policies is available here: https://www.thelancet.com/publishing-excellence
This year, The Lancet overtook the New England Journal of Medicine as the medical journal with the highest impact factor, in large part due to the papers it published about COVID-19.
We've counted retractions for three of those papers, most notably a paper about the use of the drug hydroxychloroquine that claimed to use medical data from a company called Surgisphere. As Retraction Watch readers may remember, the article was retracted after sleuths questioned if the data were real, and the company would not produce it for review.
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