The journal Heart has retracted a 2012 meta-analysis after learning that two of the six studies included in the review contained duplicated data. Those studies, it so happens, were conducted by one of the co-authors.
The article, “Low sodium versus normal sodium diets in systolic heart failure: systematic review and meta-analysis,” came from an eclectic group of authors from the United States, Canada and Italy (the first author is listed as being at a Wegmans pharmacy in Ithaca, N.Y.). The paper, published online in August 2012, purported to find that:
Compared with a normal sodium diet, a low sodium diet significantly increases morbidity and mortality in systolic [heart failure].
That conclusion should be taken with, well, you know …
The journal felt enthusiastic enough about the article — which was the second most-read paper for Heart in March 2013 — that it printed an editorial, “Low dietary sodium in heart failure: time for a re-evaluation of guidelines?” We can’t find the editorial.
But the following Editor’s note soon appeared:
It has been brought to my attention that this meta-analysis draws from a paper in the Journal of Cardiac Failure (Parrinello G, Di Pasquale P, Licata G,et al. Long-term effects of dietary sodium intake on cytokines and neurohormonal activation in patients with recently compensated congestive heart failure. J Card Fail 2009;15:864–73) containing duplicated data. The paper concerned was co-authored by Dr Di Pasquale who is also a co-author of this meta-analysis. He states the data duplication was accidental and points out that the duplicated data were not, in any event, a part of the meta-analysis. I have asked Dr Di Pasquale’s institutional director to have the Journal of Cardiac Failure paper reviewed by an independent statistician and if its propriety is confirmed, this notice will be removed.
Evidently the inquiry didn’t produce good news for the authors. According to the retraction notice:
This paper was published on-line in Heart on 21 August 2012. It reports a meta-analysis of six earlier papers.1–6 It has come to our attention that two of these papers contain duplicate data in tables reporting baseline data and treatment effects.3 4 The matter was considered by BMJ Publishing Ethics Committee. The Committee considered that without sight of the raw data on which the two papers containing the duplicate data were based, their reliability could not be substantiated. Following inquiries, it turns out that the raw data are no longer available having been lost as a result of computer failure. Under the circumstances, it was the Committee’s recommendation that the Heart meta-analysis should be retracted on the ground that the reliability of the data on which it is based cannot be substantiated.
Just to review: that’s duplicated data, which even in singular form cannot be verified — because they were eaten by a computer.
Oh, and the journal had to eat the editorial, as well:
Editor’s note Since this editorial has been published the original paper (reference 16, Di Nicolantonio JJ, Di Pasquale P, Taylor RS, et al. Low sodium versus normal sodium diets in systolic heart failure: systematic review and meta-analysis.
Heart (2012; 10.1136/heartjnl-2012-302337) has been retracted due to unreliable source data. Please find the retraction notice here; http://heart. bmj.com/content/early/2013/03/12/heartjnl-2012-302337.full.pdf+html.
As for the agglomeration of authors, James Di Nicolantonio, the Wegmans pharmacist said he first asked the last author, Daniel Hackam, a Canadian stroke expert, to help with the study, then contacted Di Pasquale:
He was the corresponding author for the trials. We wanted to make sure none of the trials were expanding cohorts.
But Di Nicolantonio seemed to dispute the retraction.
The 2 articles in question are 2 different trials (per the corresponding author), and were not even performed during the same time periods! – the trials were from 2 (non-overlapping) time periods. Additionally the corresponding author stated that these trials were not even performed at the same location. Again the “duplicated” data was not used in our meta-analysis. There is no proof that our meta-analysis is not entirely correct.