COVID-19 – time to move on?

The threat posed by COVID-19 may be receding, but the diabetes pandemic rages on and now requires our full attention, according to an opinion piece in a recent issue of Diabetologia. A study in the same issue reports that COVID-19 itself could add to the diabetes burden by triggering cases of new-onset type 2.

While COVID-19 has not gone away, it no longer threatens to overwhelm healthcare systems as it did at the height of the pandemic and, accordingly, societal restrictions have been lifted in many countries. The pandemic has had a huge impact on the work of healthcare professionals around the world. Many have had to switch their attention to caring for COVID-19 patients and have been prevented from looking after their own patients. And patients themselves have experienced restricted access to healthcare. The pandemic also led to the delay or even cancellation of many research studies. The impact, and lessons learned, from the last two years will doubtless be reflected on long and hard. But it is now time for healthcare professionals to re-focus on the other pandemic – namely the diabetes pandemic – say Diabetologia Editor-in-Chief Hindrik Mulder and Editorial Board member Tove Fall.   

Sadly, diabetes does have pandemic status. Currently, 537 million adults – one in 10 – have diabetes worldwide, and this is predicted to rise to 783 million by 2045. Diabetes claims the lives of 7 million people a year – that’s one person every five seconds. Even if it does not kill directly, it exacts a huge burden on both the individual and society in terms of symptoms and complications. Global expenditure on diabetes for adults has grown from US $232 billion in 2007 to US $966 billion in 2021, accounting for 11.5% of the global health budget.

It is hard to compare the costs of diabetes with that of COVID-19, although it looks as if the death toll may be similar, with between 12 and 22 million COVID-19 deaths in the first two years of the pandemic. Mulder and Fall note that it is striking how fearful people are when it comes to a rapidly emerging and unpredictable disease like COVID-19. Yet, by contrast, they seem to underestimate the gravity of diabetes, which limits the quality and quantity of life of those who have it, exerts a huge burden on society and, like COVID-19, has spread around the world. 

Mulder and Fall go on to praise the efforts that all involved in Diabetologia have made during the pandemic to keep our journal going as a high-quality platform for the best diabetes research. As we enter the post-pandemic era, it will be crucial to continue to highlight the importance of this work for people with diabetes and society at large. The pandemic has shown what can be achieved by collaborative efforts, focused work and joined-up leadership. It is now time to apply these virtues to the diabetes pandemic.

Does COVID-19 cause diabetes?

The COVID-19 pandemic may even intensify the diabetes pandemic, through an unwelcome legacy in the form of new cases of type 2 diabetes following infection. The SARS-CoV-2 virus is known to attack the human pancreas. Infection has been shown to reduce the number of insulin-producing granules in beta cells and it also impairs glucose-stimulated insulin secretion. The virus may act by triggering proinflammatory cytokines. It’s already known that proinflammatory pathways leading to low-grade chronic inflammation in adipose tissue play a key role in the pathogenesis of insulin resistance and type 2 diabetes. So, it is perhaps not surprising that new-onset hyperglycaemia and insulin resistance have been reported in people with COVID-19 without a prior history of diabetes. However, we don’t know yet if this is a temporary condition or whether there is a risk of persistent diabetes arising from COVID-19 infection.

Wolfgang Rathmann, of the German Diabetes Centre, Düsseldorf, and his team have investigated the incidence of diabetes after COVID-19 in patients with mild disease treated in primary care. They used the Disease Analyzer, a primary healthcare database, to study 35,865 individuals who had COVID-19 between March 2020 and January 2021 and compared them with the same number of matched individuals without the infection. This showed that incidence of all types of diabetes was numerically higher in those with COVID-19 infection, compared with those without the infection, but the difference was only statistically significant for type 2 diabetes.

Analysis showed the incidence rate of type 2 diabetes was 20.5 per 1000 person years in the COVID-19 group and 13.6 per 1000 person years in the control group. This corresponds to an increased risk of around 50%. The findings are in line with new-onset diabetes reported in a retrospective study from the UK of hospitalised COVID-19 patients, and a database study from the USA.

Insulin resistance and impaired insulin secretion have been described in people without previous diabetes who have recovered from COVID-19. It’s also known that cytokines and TNF-a continue to be upregulated after infection and this could cause beta cell dysfunction and insulin resistance. Thus, there’s a plausible mechanism for a causal relationship between COVID-19 and new-onset type 2 diabetes.

The authors conclude that if these findings are confirmed, people who have recovered from even mild COVID-19 should be screened for diabetes. And the study raises some important questions for further research. Does COVID-19 unmask pre-existing diabetes, either by immunological activation or stress hyperglycaemia? And is post-COVID-19 diabetes eventually reversed? Finally, post-COVID diabetes should be carefully managed, for cases of diabetic ketoacidosis have been observed in some individuals, sometimes months after COVID-19 infection.

To read these papers, go to:

Mulder H, Fall T. The COVID-19 pandemic may be receding but the diabetes pandemic rages on. Diabetologia online 16 March 2022. https://doi.org/10.1007/s00125-022-05683-9

Rathmann W, Kuss O, Kostev K. Incidence of newly diagnosed diabetes after COVID-19. Diabetologia online 16 March 2022. https://doi.org/10.1007/s00125-022-05670-0

For more on this topic, access our series Diabetes and COVID-19.

Any opinions expressed in this article are the responsibility of the EASD e-Learning Programme Director, Dr Eleanor D Kennedy.