Is there a relationship between vitamin D levels, inflammatory parameters, and clinical severity of COVID-19 infection?

Objectives: This study is aimed to determine the relationship between 25-OH vitamin D levels, inflammatory parameters of neutrophil‑to‑lymphocyte ratio (NLR), platelet‑to‑lymphocyte ratio (PLR), c‑reactive protein (CRP) levels and the disease severity of COVID-19 infection.

Background: Inflammation plays a key role in the pathogenesis of COVID-19 while identifying the clinical course and prognosis. The effect of vitamin D deficiency on contribution to inflammation in COVID-19 is unclear.

Methods: Based on the classification of the clinical course of COVID-19, the patients were divided into three groups, i.e., with mild (Group 1), moderate (Group 2) and severe/critical cases (Group 3). The 25-OH vitamin D values were defined as deficient, insufficient or normal.

Results: There were no statistically significant differences in the distribution rates of 25-OH vitamin D levels (p>0.05) between the groups. Inflammatory parameters in Group 3 were statistically significantly higher as compared to Groups1 and 2 (p<0.05). Multivariate logistic regression analysis revealed that NLR was an independent predictor of disease severity.

Conclusion: There is no relationship between the severity of COVID-19 infection and 25-OH vitamin D deficiency. Inflammatory parameters are associated with the disease severity, while NLR is an independent predictor of severe COVID-19. There was no correlation between 25-OH vitamin D and inflammatory markers (Tab. 4, Fig. 1, Ref. 38).