Diabetes as a risk factor for greater COVID-19 severity and in-hospital death: A meta-analysis of observational studies

Aims: To estimate the prevalence of established diabetes and its association with the clinical severity and in-hospital mortality associated with COVID-19. Data synthesis: We systematically searched PubMed, Scopus and Web of Science, from 1st January 2020 to 15th May 2020, for observational studies of patients admitted to hospital with COVID-19. Meta-analysis was performed using random-effects modeling. A total of 83 eligible studies with 78,874 hospitalized patients with laboratory-confirmed COVID-19 were included. The pooled prevalence of established diabetes was 14.34% (95% CI 12.62-16.06%). However, the prevalence of diabetes was higher in non-Asian vs. Asian countries (23.34% [95% CI 16.40-30.28] vs. 11.06% [95% CI 9.73-12.39]), and in patients aged >= 60 years vs. those aged <60 years (23.30% [95% CI 19.65-26.94] vs. 8.79% [95% CI 7.56-10.02]). Pre-existing diabetes was associated with an approximate twofold higher risk of having severe/critical COVID-19 illness (n = 22 studies; random-effects odds ratio 2.10, 95% CI 1.71-2.57; I-2 = 41.5%) and similar to threefold increased risk of in-hospital mortality (n = 15 studies; random-effects odds ratio 2.68, 95% CI 2.09-3.4 4; I-2 = 46.7%). Funnel plots and Egger's tests did not reveal any significant publication bias. Conclusions: Pre-existing diabetes is significantly associated with greater risk of severe/critical illness and in-hospital mortality in patients admitted to hospital with COVID-19. (C) 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.