Vitamin D and disease severity in coronavirus disease 19 (COVID-19)

25-OH-vitamin D [25(OH)D] deficiency (< 50 nmol/L) was associated with both a more severe systemic inflammatory response and respiratory failure in a group of hospitalized, older (mean age, 69.4 years) COVID-19 positive patients in Italy. 

Sixty-one COVID-19 positive patients admitted to the University of Verona Hospital Trust (Italy) were consecutively enrolled during the study period. The mean age was 69.4 years with 47.5% (29/61) women. 

Between March 8, 2020 and May 8, 2020 

• Among the 61 patients enrolled, 72.1% were 25(OH)D deficient (<50 nmol/L) and 57.4% had 25-OH vitamin D <37.5 nmol/L.  
• PaO2 is a measure of oxygen dissolved in arterial blood. A  normal range is typically 75-100 mm Hg. Patients in the current study with arterial PaO2 <60 mmHg had significantly lower mean 25-OH-vitamin D levels compared to patients with PaO2 ≥60 mmHg (33.3 nmol/L vs 51 nmol/L respectively, p=0.03).
• Vitamin D deficiency was associated with 3-fold higher risk of having arterial pO2 <60 mmHg. 
• 25(OH)D deficiency was also associated with increased CRP blood levels (a marker of inflammation) and difficult or labored breathing. 

• This is an observational study and no definitive assumptions on the causal role of vitamin D deficiency on COVID-19 severity can be drawn.  
• No control group has been included in the study. A similar vitamin D deficiency may be expected in subjects with baseline characteristics similar to the critically ill COVID-19 patients. 

A high prevalence of vitamin D deficiency was found in this elderly, European cohort, with approximately 70% of the patients having 25-OH-vitamin D <50 nmol/L, a threshold that is largely recognized as representing deficiency. More than half of the subjects had less than 37.5 nmol/L and approximately one out of ten had less than 12.5 nmol/L, corresponding to severe deficiency. Patients with lower (<60 mmHg)  PaO2 measured at admission had significantly lower vitamin D serum levels compared to patients with higher (≥60 mmHg) PaO2. Low vitamin D levels were also associated with higher CRP levels, suggesting more severe systemic inflammation. 

• A retrospective, observational study of COVID-19 positive patients admitted to the University of Verona Hospital Trust (Italy).  
• Demographic, clinical and biochemical parameters were collected at hospital admission, and serum 25(OH)D levels were measured.  
• The following outcomes were assessed: arterial partial oxygen pressure (PaO2); C-reactive protein (CRP); length of hospitalization; requirement of oxygen therapy; non-invasive ventilation (NIV); mechanical ventilation; and death. 

Adami, G., Giollo, A., Fassio, A., Benini, C., Bertoldo, E., Bertoldo, F., Orsolini, G., Idolazzi, L., Viapiana, O., Giannini, S., Passeri, G., Tacconelli, E., Micheletto, C., Gatti, D. and Rossini, M. (2021) ‘Vitamin D and disease severity in coronavirus disease 19 (COVID-19)’, Reumatismo, 72(4), pp. 189-196.