Against authors’ wishes, journal pulls study with errors, statistical mistake

A rheumatology journal has retracted a paper about treating knee pain after an institutional investigation found a mistake in the statistical process.

Over several months, the authors proposed a series of corrections to the 2014 study. However, the journal Annals of the Rheumatic Diseases (ARD) decided that there were “unresolved concerns” about the reliability of the data, and decided to retract the paper entirely, despite the authors’ objections.

Here’s the retraction notice:

Abou-Raya A, Abou-Raya S, Khadrawe T. Methotrexate in the treatment of symptomatic knee osteoarthritis: randomised placebo-controlled trial. Ann Rheum Dis 2014. Published Online First 27 Mar 2014. This paper has been retracted. Following publication ARD raised concerns with the authors and asked the Faculty of Medicine of the University of Alexandria to investigate. The report of the Investigation Committee included the following findings:

“Great concerns rose about the following points:

1. Aggregation of age data at the age of 60 years constituting 26.4% of the placebo group and 22.2% of the Methotrexate group despite that data is ranging between 60 to 78 years and 60 to 84 years in both groups respectively.
2. Correlation between age of the disease is evident among only the Methotrexate group (r=0.323, P=0.006) while no correlation between both variables in the placebo group (r=0.131, P=0.275).
3. Coding system of the comorbidity variable is not clear – if it is either scale variable or categorical variable – which raises concerns about validity of the method of analysis used.
4. Analysis of comorbidity (using data sent by the authors) revealed different results than that published (page 7 in output attachment).
5. Baseline VAS was nearly perfectly correlated in the placebo group with its 2nd reading at 28 weeks (r=0.927, P<0.0001), while that correlation doesn’t not even exist among the Methotrexate group (r=0.023, P=0.859).
6. “VAS mean difference” used in the paper was calculated using the mean percent difference which was not clear or mentioned in the research published.
7. Errors were made in the analysis of “VAS mean difference” by including the missing values (given the code 99) in the analysis resulting in an evident errors (Page 12 output attachment).
8. Analysis of the scores used yielding different results than that published.”

The Investigation Committee’s report concluded: “There is an unintentional mistake in the statistical process, with errors in collection of data in some groups”.

In the course of discussions with ARD about the paper, over a number of months, the authors provided three different data sets and proposed corrections to the text and two of the tables in the paper. ARD considered that the corrections to the paper were significant and was not able to agree to them for that reason and because of unresolved concerns about the reliability of the data in the paper and in the corrections. The authors do not agree with ARD’s concerns.

The 2014 paper — which found that the anti-cancer drug methotrexate reduced pain and improved function in people with knee arthritis — has not yet been indexed by Thomson Reuters Web of Science. 

Tore Kristian Kvien, editor-in-chief of ARD from the University of Oslo in Norway, told us the journal has nothing more to add to the lengthy retraction notice.

We reached out to the first author of the paper, Anna Abou-Raya, and the University of Alexandria in Egypt for further clarifications. We’ll update the post with anything else we learn.

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