Fast Five Quiz: Type 2 Diabetes Key Aspects

Romesh Khardori, MD, PhD; Anne L. Peters, MD


December 15, 2022

A strong link has been observed between glucose control and COVID-19 outcomes among hospitalized patients with preexisting T2D. One study involving 952 patients with COVID-19 and T2D showed that well-controlled blood glucose was associated with reduced risk for all-cause mortality and detrimental complications. Patients with "poorly controlled" blood glucose (n = 528), defined as the lowest fasting glucose level ≥ 3.9 mmol/L and the highest 2-hour postprandial glucose > 10 mmol/L (median, 10.9 mmol/L [196 mg/dL]) and A1c level of 8.1% had a higher mortality rate. It is now known that poor glucose control prior to hospitalization can be associated with a high risk for in-hospital death.

A retrospective study by Chen and colleagues of patients with COVID-19 and T2D found that older age, elevated C-reactive protein level, and insulin use were risk factors for mortality. Whether insulin itself is a risk factor or whether the increased mortality reflects the characteristics of the patients taking it is unclear.

Women taking metformin may be at lower risk for fatal COVID-19. In a study involving more than 6200 adults with diabetes or obesity who were hospitalized for COVID-19, fewer deaths were reported among women who had filled their 90-day metformin prescriptions. After adjustment for other risk factors, these women were 21%-24% less likely to die of COVID-19. This link was not observed among men. However, a multicenter observational study in France showed that metformin reduces the risk for COVID-related mortality in hospitalized patients, regardless of sex.

Although the risk for death from COVID-19 is significantly increased in people with both main types of diabetes, early findings suggest that the highest risk is associated with T1D.

Learn more about COVID-19 and diabetes.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.