Glucose control in the early phase of hospitalization is associated with severe prognosis in coronavirus disease 2019 (COVID-19) patients with diabetes in Japan.

Unlabelled: We investigated the association of glycemic control in the early phase of hospitalization with the prognosis of COVID-19 in patients with diabetes. We analyzed the relationship between various clinical indices, including preprandial blood glucose levels measured by self-monitoring devices in the early phase after admission, and severe prognosis in 189 patients with complicated diabetes who were admitted to our hospital between February 22, 2020 and June 20, 2021. Enrolled patients had a median age of 72 years, median body mass index of 24.7, median HbA1c of 7.1%, and median mean preprandial capillary glucose (PPCG) of 179.1 mg/dL. Sixty-six patients progressed to severe disease, and the mean PPCG in severe cases was significantly higher than that in non-severe cases, 195.2 vs 167.8 mg/dL ( = 0.005). Analysis of the receiver operating characteristic curve showed that 179 mg/dL was the cut-off value, and the risk of severity was significantly higher in patients with a mean PPCG of 180 mg/dL or higher (odds ratio (OR) 3.210,  = 0.017) in multiple regression analysis. In this study, we found that the risk of severe COVID-19 increased in patients with a high mean PPCG in the early phase of hospitalization, suggesting that good glucose control in the early phase of COVID-19 with diabetes may be effective in preventing disease severity.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13340-023-00656-8.