Deciphering Changes in Diabetes-Related Mortality Before and During the COVID-19 Pandemic

Diabetes mellitus disease continues to be a worldwide health crisis. Few discrete disease processes contribute more to global morbidity and mortality than diabetes, whether it be mortality secondary to glycemic effects on the cardiovascular system or disability related to neuropathy and vision loss.

The advent of the global COVID-19 pandemic in 2020 changed everything. It became difficult to determine what alterations in trends could be attributed to organic healthcare-related interventions, or the lack thereof, versus secondary effects related to widespread COVID-19 infections.

It has been reported by the International Diabetes Federation that 12.2% of all deaths globally in 2021 were adults diagnosed with diabetes.¹ Further, mortality rates for diabetic adults had been trending down prior to 2014, then stabilizing since 2017.² Since these data were published more recent reports point to an increase in deaths among adults with diabetes coinciding with the beginning of the COVID-19 pandemic.³

Unfortunately, data from the National Vital Statistics System are not specific making the true underlying cause of death difficult to determine. Diabetes is often listed as an underlying condition, but more information is needed to attribute diabetes as the cause-specific feature contributing to mortality in this population.

Donghee Kim, MD, PhD, a researcher at Stanford University, along with colleagues examined national mortality records from 2017-2020 in an effort to determine trends in all-cause and diabetes-related mortality with specific context to the beginning of the COVID-19 pandemic.

They included 1,218,968 deaths listed with an underlying condition of diabetes. Cause-specific mortality included: 373,802 deaths from cardiovascular disease (CVD), 358,439 from diabetes, 124,881 from cancer, 2,310, from kidney disease, and 62,595 from COVID-19 (2020).³

Overall, there was a steady 2.4% increase in all-cause mortality due to diabetes during the period studied, however, rates were steady from 2017 until the end of 2019.³ The increase observed is attributed to a very sharp rise in all-cause mortality among diabetic adults between the last quarter of 2019 and the third quarter of 2020, the first year of the COVID-19 pandemic.³

Cause-specific mortality in diabetic adults was also examined. Rates for both death from cardiovascular disease and renal disease remained stable before and during COVID-19.³ Cancer-related mortality in diabetics was stable before COVID-19 but increased at a rate of 3.9% during the pandemic.³ It is unclear why cancer-related diabetic deaths increased during the COVID-19 pandemic.

As expected, COVID-19-related mortality in diabetic adults mirrored increases in COVID-19 infections with a 9-fold increase from quarter 1 in 2020 to quarter 4.³ This trend accounted for the rise in all-cause mortality. During the pandemic the proportion of CVD, diabetes, cancer, and renal disease-related mortality decreased while annual trends per cause remained stable.3 This effect may have been due to fewer adults seeking care for other conditions during the COVID-19 pandemic. The rise in diabetics succumbing to COVID-19 was so sharp during 2020 that it reached parity with both cardiovascular disease and diabetes cause-related death (approx. 24% of deaths).³

The authors make brief note that patients are generally at higher risk for death from COVID-19 if they have other comorbidities such as diabetes. Diabetes may make individuals more susceptible to poorly regulated inflammatory states and cytokine storm. Some studies place that additional risk as high a 4-fold over the general population.³

Although coding on death certificates as well as inconsistencies in reporting may account for variations in validity, it is unlikely that such factors could contribute enough to produce such dramatic results. This study shows both the sheer magnitude of the COVID-19 effect on overall mortality statistics in 2020 and the relative risk increase for diabetics. While these data seem intuitive and concise, I believe they also point to a post-COVID-19 era that may see dramatic increases in comorbid deaths from all causes.

We have seen a relative lack of willingness to visit clinics and hospitals during the pandemic. Reductions in various disease-related visits and treatments are deceptive. If and when patients come back for care, it is likely that they will be sicker leading to increased deaths and overall disease burden. We will not know for years what the true cost of this global pandemic will be but those of us on the front lines should continue to urge patients to seek care both acute and preventative lest we erase decades of progress.

References:

1. International Diabetes Federation. IDF Diabetes Atlas, 10th edition. Accessed 14 February 2022. Available from www.diabetesatlas.org
2. Kim D, Li AA, Cholankeril G, et al. Trends in overall, cardiovascular and cancer-related mortality among individuals with diabetes reported on death certificates in the United States between 2007 and 2017. Diabetologia 2019;62: 1185–1194
3. https://diabetesjournals.org/care/article/doi/10.2337/dc22-0348/145033/Trends-in-All-Cause-and-Cause-Specific-Mortality