Understanding COVID and Diabetes: Ominous Findings, Next Steps

Edward W. Gregg, PhD; Mark Harmel, MPH


July 01, 2021

Some of you may know that I worked at the Centers for Disease Control and Prevention for 20 years before coming to England, and I really focused on diabetes epidemiology. The COVID-19 pandemic, in addition to having a huge impact on life, has had a very unexpected and dramatic impact on the way we do our work, in the outlook for epidemiology and its role in diabetes.

Epidemiology and Public Health in the Spotlight

First, it's raised the profile of what we do in epidemiology and public health in a major way. For years, when I would travel on an airplane and talk with the person next to me, and they'd ask me what I do, I would say, "I'm an epidemiologist." But I got tired of explaining that, no, I'm not a skin doctor. After a while, I started to say, "I'm a health scientist."

Well, those days are over now. People know what epidemiologists are and they know what public health is about. The interest in what we do, and knowledge of its importance, has increased a whole lot.

This pandemic has created new demands and changes in the way we do things. In the past, we often had a 2- to 3-year time horizon for doing studies and trying to influence decisions. Part of that was a function of chronic conditions. But I think we've learned from this pandemic, where the demands to make decisions about what to do out in the public were almost immediate, that getting data to help with those decisions very quickly is going to be a requirement in the future — continuously for COVID-19, but I think the expectation is going to be there for other conditions as well.

We'll also be required to use available real-world data in ways that we haven't in the past. In the past, we would set up surveys or develop trials or interventions. And those are still, of course, very important. But the ability to find, integrate, and use the data out there very quickly to help us make decisions in a short period of time is going to increase as well.

The Role of Diabetes in COVID Morbidity and Mortality

The way this has influenced what we've seen for diabetes and COVID-19 has been profound as well. We saw within a month of the pandemic that diabetes had an important role. It's clear that diabetes is one of the core factors driving poor outcomes in people who have COVID-19. A person with diabetes is more than twice as likely to be hospitalized. If they're hospitalized, risk of death is about 25%, two- to threefold higher than a person without diabetes, and 20%-40% end up in intensive care.

And those are just what we know from data from during that month of hospitalization when it's measured. There are other repeated hospitalizations and other aspects on morbidity for which we don't have good data.

One of the most ominous findings has been that the overall mortality rate among people with diabetes is 50% higher than in previous years. That's in comparison with the general population, where we see that the COVID-19 pandemic has been really damaging as well; it's had a 20% increase. This essentially amounts to two and a half times the impact for the population with diabetes compared with the general population, and this is a reflection of the impact that COVID-19 can have not only on the risk for hospitalization but also the risk for further morbidity and mortality.

What's Needed Going Forward

On the one hand, the proliferation of data in such a short period of time has been truly amazing. The number of studies published can be a bit overwhelming at times. But when we look at the epidemiology of diabetes and COVID-19, it's actually been a bit narrow and focused on what happens from the point of hospitalization on. But for us to really get a handle on reducing the damage to the population with diabetes, we need to broaden that view quite a bit.

We need to understand how diabetes influences risk for [SARS-CoV-2] transmission or infection in the first place, how it influences the degree of morbidity or the severity, and particularly how the indirect effects of the pandemic influence the population with diabetes. For example, how are behaviors affected? How is care? How are complications affected? How is the deferral of health services influencing things like diagnosis and occurrence of other conditions?

And there might be some unintended benefits of the pandemic that are occurring too, such as changes in care or changes in behavior that affect some segments of the population in positive ways. Those are going to be the questions that are important to study, using diverse data sources, in the year to come.

Eighteen months ago, when it was apparent that we were confronted by a global pandemic, many of us were optimistic that we would have to tackle this for a short period of time and then we would be done with it. And although some countries in the world are now seeing encouraging rates [of disease] and rates of vaccination that make the future look better, it's also apparent that we have a long way to go. The importance of epidemiology in influencing how we prevent and treat COVID-19 in populations with and without diabetes is only going to grow in the years to come. We have a lot left to do and a lot left to learn.

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