A pairwise comparison of subgroups, depending on the therapy, revealed a statistically significantly lower level of albumin-adjusted calcium on 3rd day among patients on baricitinib monotherapy or combined with tocilizumab compared with a subgroup of patients undergoing etiotropic treatment (2.16 [2.13; 2.18] mmol/l vs 2.23 [2.19; 2.28] mmol/l, p=0.002, U-test, Bonferroni correction p0=0.012).CONCLUSION: Patients with severe coronavirus infection are characterized by a high prevalence of vitamin D deficiency and hypocalcemia. Here, ALB is linked to vitamin D deficiency.