Diabetes Mellitus and COVID-19: A Bad Prognosis Association

  

    
Type    of comobidity 
    
(%) 
  
  

    
Hypertension 
    
73.8 
  
  

    
Diabetes mellitus 
    
33.9 
  
  

    
Ischemic heart disease 
    
30.1 
  
  

    
Atrial fibrillation 
    
22 
  
  

    
Chronic renal failure 
    
20.2 
  

Table 1: Main Comorbidities Associated with COVID-19 infection in Italy.

Many mechanisms can explain the bad prognosis of COVID-19 in diabetics, but they remain hypothetical, several factors have been mentioned in the literature

Type 2 diabetes, often associated with obesity predisposes to a pro-inflammatory state via increased inflammatory mediators IL-6 and TNF-a, which might facilitate the cytokine storms, which in turn appears to be the cause of the severe cases of Covid-19 pneumonias and of death of many patients. A high mortality rate in the presence of chronic complications of diabetes, particulary macrovasculars, was raised in Chines series and confirmed in the French study [8,9]. Inflammation increases insulin resistance and the need for insulin, which affects glycoregulation and increases the risk of ketoacidosis, on the other hand SARS-Cov-2 could directly damage beta cells, this hypothesis has been raised to explain the large number of new cases of diabetes and also the need for high doses of insulin in infected patients. Indeed pancreatic beta cells express also the ACE2 receptor (the coronavirus binding site), such as lung, heart and kidney cells [3]. This hypothesis suggests screening for diabetes in patients with COVID-19 infection. Hypercoagulability appers also to be the cause of the severe cases of Covid-19 pneumonias. It is known that diabetes is associated with hypercoagulability and endothelial dysfunction which is only partially corrected by optimal glycemic control. In addition the association with a procoagulant infection by the cytokine storms will increase hypercoagulability, this explains why the level of D-dimer was significantly higher in diabetic patients infected with the coronavirus in several series [9,10]. Conversely, hypoglycemia increases also the inflammatory state and platelet reactivity, this is why strict glycemic control during coronavirus infection could be deleterious. So rigorous monitoring of capillary blood glucose and therapeutic adaptations are strongly recommended, especially in the case of treatment with hydroxychloroquine. The latter, with an unknown hypoglycemic action, is approved by most African medical societies for the treatment of SARS-Cov-2 in combination with azithromycin. Finally, an even more worrying aspect of the interaction of two pandemics, is the asymptomatic character in the initial phase of the infection which was noted in the Chineses series, with less fever, chills and shortness of breath. This could be responsible for a delay in treatment and an increase in the incidence of severe forms [9].

Conclusion

In light of these findings and seen the high prevalence of diabetes on the African continent, particularly in North Africa (12.2%), there are a threat of increased incidence of morbidity and mortality linked to COVID-19. In addition to chronic complications, the pneumonia caused by COVID-19 worsens the prognosis of our diabetic patients. We must pay particular attention to this fragile population, with more time and resources, especially for the elderly, obese or those with chronic complications of diabetes who have a high risk of developing severe forms. Without forgetting that COVID-19 infection is an opportunity to screen for diabetes. The future research will explain on the behaviour of COVID-19 in patients with diabetes.

Competing Interests

The authors declare no competing of interests.

Authors’ Contributions

All the authors contributed equally in drafting of the manuscript. All the authors read and agreed to the final manuscript.

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