ABSTRACT
Background and Aim: Vitamin D is a hormone with essential roles in both cellular metabolism and immunity. It controls calcium homeostasis and modulates innate and adaptive immune system responses. Many studies suggested an association between vitamin D deficiency and clinical outcomes of covid-19 infection, while others failed to document such a relation. The present study aimed to evaluate the clinical and prognostic significance of baseline vitamin D levels in hospitalized Egyptian covid-19 patients. Patients and Methods: The present retrospective study included 300 hospitalized covid-19 patients. Patients were submitted to standard clinical, laboratory, and radiological assessment. According to vitamin D levels, patients were classified to have normal levels (≥30), insufficient levels (20-29) or deficient levels (<20). Results: According to their vitamin D levels, patients were classified into those with normal vitamin D (n=135), others with vitamin D insufficiency (n=114), and a third group with vitamin D deficiency (n=51). Patients with normal vitamin D levels and vitamin D insufficiency are significantly younger [median (IQR): 49.0 (39.0-57.0) versus 51.0 (40.0-61.0) and 55.0 (43.0-62.0) years, respectively, p=0.012] and had less frequency of severe disease (24.4% versus 40.4% and 51.0%, respectively) when compared with those with vitamin D deficiency. Moreover, they had significantly lower levels of D dimer [median (IQR): 1.5 (0.9-2.5) versus 1.8 (0.9-3.1) and 2.0 (1.0-3.2)], CRP [median (IQR): 58.0 (30.0-120.0) versus 76.0 (42.5-160.0) and 105.0 (74.0-208.0), respectively, p<0.001], ferritin [median (IQR): 458.0 (240.0-759.0) versus 606.0 (433.8-897.8) and 820.0 (552.0-1087.0), respectively, p<0.001], and procalcitonin [median (IQR): 290.0 (152.0-394.0) versus 372.5 (227.0-530.5) and 443.0 (272.0-575.0), respectively, p<0.001]. Only lower vitamin D levels were significant predictors of mortality in multivariate analysis [OR (95% CI): 0.88 (0.84-0.92), p<0.001]. Conclusion: Low vitamin D levels are related to exaggerated inflammatory response, disease severity, and poor clinical outcome in hospitalized covid-19 patients.