OBJECTIVE An important prognostic factor in any form of infection seems to be glucose control in patients with type 2 diabetes mellitus. There is no information about the effects of tight glycemic control on Covid-19 outcomes in patients with hyperglycemia. Therefore, we examined the effects of optimal glycemic control in patients with hyperglycemia affected by Covid-19.

RESEARCH DESIGN AND METHODS Fifty-nine patients with Covid-19 hospitalized with moderate disease were evaluated. On the basis of admission glycemia >7.77 mmol/L, patients were divided into hyperglycemic and normoglycemic groups. Interleukin 6 (IL-6) and D-dimer levels were evaluated at admission and weekly during hospitalization. The composite end point was severe disease, admission to an intensive care unit, use of mechanical ventilation, or death.

RESULTS Thirty-four (57.6%) patients were normoglycemic and 25 (42.4%) were hyperglycemic. In the hyperglycemic group, 7 (28%) and 18 (72%) patients were diagnosed with diabetes already before admission, and 10 (40%) and 15 (60%) were treated without and with insulin infusion, respectively. The mean of glycemia during hospitalization was 10.65 ± 0.84 mmol/L in the no insulin infusion group and 7.69 ± 1.85 mmol/L in the insulin infusion group. At baseline, IL-6 and D-dimer levels were significantly higher in the hyperglycemic group than in the normoglycemic group (P < 0.001). Despite that all patients were on standard treatment for Covid-19 infection, IL-6 and D-dimer levels persisted higher in patients with hyperglycemia during hospitalization. In a risk-adjusted Cox regression analysis, both patients with hyperglycemia and patients with diabetes had a higher risk of severe disease than those without diabetes and with normoglycemia. Cox regression analysis evidenced that patients with hyperglycemia treated with insulin infusion had a lower risk of severe disease than patients without insulin infusion.

CONCLUSIONS Insulin infusion may be an effective method for achieving glycemic targets and improving outcomes in patients with Covid-19.