Background: Patients with diabetes or hyperglycemia have poor prognosis when infected with coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
Objective: To review the impact of hyperglycemia and its treatment on prognosis of hospitalized patients with COVID-19.
Methods: Review of English literature by search of electronic databases: Pub/MEDLINE until June 23, 2020. Search terms included diabetes, hyperglycemia, COVID-19, insulin, metformin, hydroxychloroquine. Retrospective studies, meta-analyses, pertinent reviews, and consensus guidelines are reviewed.
Results: Diabetes is the second co-morbidity after hypertension in patients with COVID-19 disease. Yet, after controlling for age, prevalence of diabetes in COVID-19 patients is similar to the general population. Patients with diabetes and COVID-19 have poor prognosis and higher mortality compared with patients without diabetes. Hyperglycemia irrespective of prior diagnosis of diabetes is associated with adverse outcomes among COVID-19 patients. Blood glucose (BG) levels should be lowered below 180 mg/dl. Insulin is the standard therapy to control hyperglycemia in hospitalized patients. Metformin may be continued in mild cases of COVID-19 in absence of contraindications. The anti-diabetic effect of hydroxychloroquine can be virtually beneficial in COVID-19 patients with type 2 diabetes.
Conclusions: Hyperglycemia is associated with poor outcomes in patients with COVID-19. Control of BG below 180 mg/dl by insulin therapy remains the standard of care. Randomized trials are needed to define the optimum range of BG and determine the safety and efficacy of metformin and hydroxychloroquine in hospitalized patients with COVID-19.
COVID-19, Diabetes, Hyperglycemia, Insulin, Metformin, Hydroxychloroquine, Mortality