Is newly diagnosed diabetes a stronger risk factor than pre‐existing diabetes for <scp>COVID</scp>‐19 severity?

Abstract

We read with great interest the article by Aggarwal et al published in the July issue of the Journal of Diabetes.1 In this meta-analysis of 16 studies, the authors have shown that coronavirus disease 2019 (COVID-19) patients with pre-existing diabetes are about two times more likely to experience severe illness or in-hospital mortality compared to those without diabetes. We would like to add further that recent and emerging evidence suggests that newly diagnosed diabetes may confer a greater risk for poor prognosis in COVID-19 patients than pre-existing diabetes. In a study by Li et al of 453 COVID-19 patients in China, compared with those with pre-existing diabetes (n = 98, 21.6%), newly diagnosed diabetes patients (n = 94, 20.8%) were more likely to require intensive care unit (ICU) admission (4.1% vs 11.7%) and invasive mechanical ventilation (9.2% vs 11.7%).2 In addition, compared with normal glucose, newly diagnosed diabetes was associated with nearly a 10-fold increased risk of mortality (adjusted hazard ratio [aHR] 9.42; 95% CI, 2.18, 40.7), whereas pre-existing diabetes had only a 5-fold higher risk (aHR 4.63; 95% CI, 1.02, 21.0). In a study by Bode et al from the United States of 1122 COVID-19 patients, 41.7% (40/96) of those with newly diagnosed diabetes died during hospitalization compared with 14.8% (13/88) of those with pre-existing diabetes (P < .001).3 Among those who survived, patients with newly diagnosed diabetes had a longer hospital stay than those with pre-existing diabetes (mean: 6.8 vs 5.8 days, P < .001). In a study by Zhang et al of 166 COVID-19 patients admitted to Tongji Hospital in China, 21 (12.7%) had newly diagnosed diabetes.4 These 21 patients had significantly higher levels of certain markers of multi-organ damage, including alanine and aspartate transaminase and lactate dehydrogenase, and cytokines such as interleukin-8 than those with pre-existing diabetes (n = 61, 36.7%) (all P < .05). In a study by Fadini et al of 413 COVID-19 patients in Italy, compared with no diabetes (n = 306, 74.1%), newly diagnosed diabetes (n = 21, 5.1%) showed a stronger association with the composite outcome of ICU admission or death than pre-existing diabetes (n=86, 20.8%) (relative risk: 2.60 vs 1.24, P < .001), after adjusting for age and sex.5 In a more recent study from Italy by Lampasona et al of 509 COVID-19 patients, the Kaplan-Meier curves showed lower rates of survival over 10 weeks in those with newly diagnosed diabetes (n = 49, 9.6%) compared with those with pre-existing diabetes (n = 90, 17.7%) (P < .001).6 The limited available evidence suggests that newly diagnosed diabetes may confer a greater risk of severe illness and mortality in COVID-19 patients than pre-existing diabetes. Thus, it is important to screen all COVID-19 patients with blood glucose and glycosylated hemoglobin to identify those with newly diagnosed diabetes7 and monitor them closely for in-hospital complications, thereby improving the prognosis of these patients. No funding received. None declared.

Topics & Concepts