Glycemic Control a Risk Factor for Poor COVID-19 Outcomes Among Patients With Type 2 Diabetes

We review the role of a new class of agents in improving glycemic control and reducing diabetes-related vascular disease.
We review the role of a new class of agents in improving glycemic control and reducing diabetes-related vascular disease.
A team of investigators sought to identify the relationship between glycated hemoglobin and outcomes in patients with type 2 diabetes and COVID-19 infection.

Poor glycemic control was found to be associated with increased risk for COVID-19 hospitalization and mortality, according to the results of a retrospective study published in Diabetes Care.

Data for this study were sourced from the National COVID Cohort Collaborative (N3C), a longitudinal, multicenter cohort comprising US patients with COVID-19. Patients (N=39,616) with type 2 diabetes (T2D) were assessed for 30-day outcomes on the basis of glycemic control.

The patient population consisted of 50.9% women; mean age was 62.1±13.9 years, and mean glycated hemoglobin (HbA1C) was 7.6%±2.0%. Approximately one-half of the study participants were White (55.4%), 49.0% were hospitalized, 7.0% received invasive ventilation or extracorporeal membrane oxygenation (ECMO), and 5.7% died. The cohort of patients who did not survive were more often men and older, and had a lower body mass index (BMI) and a higher prevalence of all comorbidities (all P <.01) except mild liver disease and HIV.

Among patients who were hospitalized, the mean length of stay was 11.7±18.1 days.

Stratified by HbA1C, mortality risk was increased among patients with values greater than 10% (adjusted hazard ratio [aHR], 1.46; 95% CI, 1.24-1.71; P <.001), values from 9% to less than 10% (aHR, 1.37; 95% CI, 1.15-1.63; P <.001), and values from 8% to less than 9% (aHR, 1.40; 95% CI, 1.22-1.60; P <.001). Patients with HbA1C ≥7% were at increased risk for hospitalization (aHR range, 1.23-2.32; all P <.001) and need for invasive ventilation or ECMO (aHR range, 1.24-1.6; all P <.001).

Additional risk factors for mortality were age 80 years and older (aHR, 2.84; P <.001), age 70 to 79 years (aHR, 1.8; P <.001), severe liver disease (aHR, 1.74; P <.001), BMI <20 kg/m2 (aHR, 1.72; P <.001), dementia (aHR, 1.45; P <.001), renal disease (aHR, 1.41; P <.001), male sex (aHR, 1.41; P <.001), heart failure (aHR, 1.38; P <.001), Hispanic or Latino ethnicity (aHR, 1.35; P <.001), BMI 20 to 24.9 kg/m2 (aHR, 1.22; P =.00361), BMI  40 kg/m2 and greater (aHR, 1.16; P =.0443), and insulin use (aHR, 1.14; P =.00548).

Decreased risk for mortality was observed among patients aged younger than 60 years and users of metformin, a sulfonylurea, sodium-glucose cotransporter inhibitors, and glucagon-like peptide-1 analogs.

Similar trends were observed for hospitalization and ventilation risks.

This study was limited by not having sufficient data to subdivide patients on the basis of diabetes duration.

These data indicated that patients with T2D with poor glycemic control were at increased risk for hospitalization and mortality from COVID-19.


Wong R, Hall M, Vaddavalli R, et al; for the N3C Consortium. Glycemic control and clinical outcomes in U.S. patients with COVID-19: data from the National COVID Cohort Collaborative (N3C) Database. Diabetes Care. 2022;dc212186. doi:10.2337/dc21-2186