Previous pandemics caused by severe acute respiratory syndrome (SARS), H1N1 influenza, and Middle East respiratory syndrome (MERS) are known to cause more severe symptoms in diabetic patients.1 Similarly, in the recent epidemiological studies, diabetes has been consistently identified as one of the major comorbidities associated with coronavirus disease 2019 (COVID-19).2,3 A study assessing the diabetic patients hospitalized for COVID-19 in France showed that 10% of the patients die within 7 days of admission, while 20% required mechanical ventilation at day 7. The study also noted that body mass index (BMI), age, and sex were independently associated with COVID-19 morbimortality, but not the glycaemic control.1
Diabetic patients are generally more susceptible to infectious diseases as a hyperglycaemic environment favours immune dysfunction.4 Consequently, diabetic patients have a higher infection risk for influenza and pneumonia, and were identified to be under major mortality risk during the SARS, 2009 H1N1, and MERS pandemics.1 It was recently noted that a significant proportion of COVID-19 patients admitted into the intensive care unit (ICU) were diabetic, with a meta-analysis demonstrating that diabetes was associated with a more than doubled risk for ICU admission (OR=2.79; 95% CI: 1.85-4.22) and a more than tripled risk for death (OR=3.21; 95% CI: 1.82-5.64).5 Nonetheless, information regarding the relationship between diabetic phenotypes and more severe COVID-19 presentations are lacking.1
Results of the Coronavirus SARS-CoV-2 and Diabetes Outcomes (CORONADO) study were recently published in Diabetologia. The aim of the study was to describe the phenotypic characteristics and prognosis of individuals admitted to hospital with COVID-19. 1,317 patients were selected from all French hospitals, with 89% of them diagnosed with type II diabetes, 3% with type I, and the rest with other diabetic aetiologies.1
Patients were observed for the composite primary outcome of tracheal intubation and death at day 7 of hospitalization. Secondary outcomes include tracheal intubation, death at day 7 of hospitalization, admission to ICU, and discharge from hospital. A univariate logistic regression model was used to assess the odds ratio of the primary outcome, and a multivariable logistic regression model was used to assess the association of the primary outcome and death on day 7 with other clinical and biological factors.1
At the end of the 3-week study, 29.0% (95% CI: 26.6-31.5) of the patients met the primary outcome, with 20.3% (95% CI: 18.1-22.5) requiring tracheal intubation for mechanical ventilation and 10.6% (95% CI: 9.0-12.4) died during the 7-day observation period. In addition, 31.1% (95% CI: 28.6-33.7) of the patients were admitted into ICU and 18.0% (95% CI: 16.0-20.2) were discharged on day 7.1
Univariate analysis showed that patients who met the primary outcome were primarily male (69.1% vs. 63.2%, p=0.0420), had a high BMI (median 29.1 [95% CI: 25.9–33.6] vs. 28.1 [95% CI: 24.8–32.0]kg/m2, p=0.0009), and were prescribed renin-angiotensin-aldosterone system blockers (61.5% vs. 55.3%, p=0.0386) when compared to those who did not meet the primary outcome.1
The age- and sex-adjusted multivariate analysis supported a significantly positive association between BMI and the primary outcome (adjusted OR=1.28; 95% CI: 1.10-1.47, p=0.0010), but not with death on day 7 (p=0.1488). HbA1c level, albeit strongly associated with diabetes, was notably neither associated with the primary outcome nor death on day 7. Other factors including age (especially in age >75), hypertension, micro- and macrovascular diabetic complications, and comorbidities such as heart failure or treated obstructive sleep apnoea (OSA) were also found to be independently associated with the risk of death on day 7.1
To conclude, the CORONADO study has identified high risk phenotypes of diabetic COVID-19 patients and has demonstrated a primary association between BMI and severe COVID-19 presentation, but not chronic glycaemic control. Age and sex were also shown to be independent factors for the increased mortality, particularly the elderly diabetic populations with advanced complications were at risk of early death.1
1. Cariou B et al. (2020). Phenotypic characteristics and prognosis of inpatients with COVID-19 and diabetes: The CORONADO study. Diabetologia, 63(8), 1500-1515.
2. Xu X et al. (2020). Seroprevalence of immunoglobulin M and G antibodies against SARS-CoV-2 in China. Nature Medicine.
3. Apicella M et al. (2020). COVID-19 in people with diabetes: Understanding the reasons for worse outcomes. The Lancet Diabetes & Endocrinology, S2213858720302382.
4. Alves C et al. (2012). Infections in patients with diabetes mellitus: A review of pathogenesis. Indian Journal of Endocrinology and Metabolism, 16(7), 27.
5. Roncon L et al. (2020). Diabetic patients with COVID-19 infection are at higher risk of ICU admission and poor short-term outcome. Journal of Clinical Virology, 127, 104354.