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expert reaction to study looking at rates of newly diagnosed type 2 diabetes after mild COVID-19 disease

A study published in Diabetologia looks at incidence of newly diagnosed diabetes after COVID-19.


Dr Betty Raman, senior clinical research fellow in the Radcliffe Department of Medicine, University of Oxford, said:

Is this robust science; what are the strengths and limitations?

“This is an important paper and in keeping with other evidence suggesting rising incidence of diabetes and cardiovascular disease after COVID-19.

“The strengths are the large numbers and the use of a viral infection control group.  The limitations are the retrospective nature that uses electronic medical health records.  There is a potential for increased vigilance and testing due to a heightened awareness of the risks associated with COVID-19 and hence an associated tendency for increased diagnosis.  Also as the author states, the persistent inflammatory state may have unmasked an inherent tendency in some people to develop diabetes and whether this will improve over time is currently unknown.

Does the press release accurately reflect the science?


Is this good quality research?  Are the conclusions backed up by solid data?


How does this work fit with the existing evidence?

“This is in keeping with some papers that have looked at follow up data from patients recovering from COVID, although those were in more severe disease.

“What is surprising is that the increased incidence of diabetes here is seen in mild infections.  Further validation of these findings in an independent external cohort would therefore be really important.

Have the authors accounted for confounders?  Are there important limitations to be aware of?

“Propensity score matching was used and so both groups are reasonably well matched, but it is possible that there is residual confounding which were not captured by electronic health records.  As this study was conducted on data collected from March 2020-Jan 2021, it is unclear if this risk will still be seen in a vaccinated population infected with newer variants.

What are the implications in the real world?  Is there any overspeculation?

“These are important findings with huge implications given the that nearly half a billion people globally have been affected by SARS-CoV-2 infection.

“There are some caveats.  This analysis was carried out for patients with a diagnosis of COVID-19 from March 2020 to Jan 2021 (so Wuhan and Kent variant) and pre-vaccine.  It is hard to know if these results can be extrapolated to patients infected with milder variants and those who have been vaccinated.

Does this study convincingly suggest there are higher rates of newly diagnosed type 2 diabetes after infection with mild COVID-19?

“There is a strong signal seen, but further validation of these findings in an external cohort is needed.”


Prof Naveed Sattar, Professor of Metabolic Medicine, University of Glasgow, said:

“This is interesting but I would caution that the top line message is perhaps too premature as the study is still quite small and the findings remain marginal.  This means any unaccounted for factor could have led to the results rather than there being a true link between COVID-19 and diabetes risk.

“For example, we know that people who developed more severe COVID-19 disease were heavier than those who would normally be admitted with pneumonia and whilst the authors appear to have adjusted for obesity rather than continuously measured BMI, there may be things still unaccounted for that could have impacted the results.

“The authors themselves realise their work is preliminary.  Larger datasets are needed to test this important question.”



‘Incidence of newly diagnosed diabetes after Covid-19’ by Wolfgang Rathmann et al. was published in Diabetologia at 23:01 UK time on Wednesday 16 March 2022.

DOI: 10.1007/s00125-022-05670-0



All our previous output on this subject can be seen at this weblink:



Declared interests

Prof Naveed Sattar: “No COI.”

None others received.



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