Long-Term HbA1c Helps Predict Risk of COVID-19 Disease Severity

A retrospective study leveraging 2-3 years of data found long-term HbA1c control was a greater predictor of COVID-19 severity than a single, contemporary HbA1c measurement as other studies have examined.

New research from an analysis examining medical record data from more than 16,000 patients from 2017-2020 is providing clinicians with insight into factors that could help predict patients with diabetes at a greater risk of severe COVID-19.

Performed by investigators at the Rensselaer Polytechnic Institute and Icahn School of Medicine at Mount Sinai, the study examined the impact of various factors on disease severity among patients with type 2 diabetes, including HbA1c levels and impact of common medications. Results of the study suggest long-term glycemic control offered the most accurate risk prediction, with investigators pointing out those with poor long-term glycemic control were nearly 50% more likely to be hospitalized in an intensive care unit.

“People knew that diabetes was a risk factor for COVID-19-related outcomes, but not all diabetic patients are the same. Some people have a longer history of diabetes, some have more severe diabetes, and that has to be accounted for,” said Deepak Vashishth, corresponding author, professor of biomedical engineering, and director of the Center for Biotechnology and Interdisciplinary Studies at Rensselaer Polytechnic Institute, in a statement. “What this study does is to better stratify the level of diabetes within the population, so diabetic patients aren’t treated as a single population without any differences among them.”

As the COVID-19 pandemic continues to wreak havoc on global and national health systems, few patient groups have been as thoroughly examined for their potential risk from developing the disease as patients with diabetes. Although many studies have examined potential risk factors for increased disease severity in patients with diabetes, investigators noted most had examined more contemporary trends rather than long-term factors that could provide prognostic value.

With this in mind, investigators designed their endeavor as a retrospective cohort study using anonymized data from within the OptumLabs Data Warehouse from January 2017 to November 2020. From their search, investigators identified a cohort of 16,504 patients with type 2 diabetes who contracted COVID-19. For the purpose of analysis, investigators planned to assess the association between 2 and 3-year HbA1c average, medication use between COVID-19 diagnosis and ICU admission, and risk of intensive card related to COVID-19 using both univariate and multivariate modeling.

After adjustment for covariates, results of the investigators’ analyses indicated the risk of requiring intensive care increased by 12% (HR, 1.12 [95% CI, 1.09-1.25]; P <.001) for every 1% increase in HbA1c and 48% (HR, 1.48 [95% CI, 1.34-1.63]; P<.001) greater among those with an HbA1c of 9% or greater when compared to those with adequate glucose control. Further analysis suggested use of corticosteroids and the combined use of insulin and metformin was associated with a significant reduction in risk of being admitted to intensive care. Conversely, there was no observed reduction in risk of being admitted to intensive care based on use of ACE inhibitors or ARBs among patients.

“We find that two- to three-year longitudinal glycemic levels better indicate the risk of COVID-19 severity than measurements which look at a shorter period of time,” said Bowen Wang, first author and a doctoral student in Vashishth’s lab, in the aforementioned statement. “We hope these insights aid physicians in better treating and managing high-risk patients.”

This study, “Evaluation and management of COVID-19-related severity in people with type 2 diabetes,” was published in BMJ Open Diabetes Research & Care.