Correlation of vitamin D levels with serum parameters in Covid-19 patients

BACKGROUND: It is well-established that vitamins have many beneficial roles and protect humans against inflammatory diseases. Vitamin D, a lipid-soluble vitamin, plays a crucial role in viral infections. Therefore, this study aimed to investigate if serum 25(OH)D levels affect morbidity, mortality, and levels of inflammatory parameters in COVID-19 patients. METHODS: 140 COVID-19 patients participated in this study (65 outpatients and 75 inpatients). Their blood samples were collected to determine TNFα, IL-6, D-dimer, zinc, Ca(2+), and 25(OH)D levels. Patients with O(2) saturation <93% were admitted and hospitalized in the infectious disease ward (inpatient group). Patients with O(2) saturation >93% received routine treatment and were discharged (Outpatient group). RESULTS: The serum levels of 25(OH)D in the inpatient group were significantly lower than those in the outpatient group (p < 0.001). Serum TNF-α, IL-6, and D-dimer levels in the inpatient group were significantly higher than those in the outpatient group (p < 0.001). Serum TNF-α, IL-6, and D-dimer levels were inversely correlated with 25(OH)D levels. No significant differences were observed in the serum levels of zinc and Ca(2+) between the studied groups (p = 0.96, p = 0.41 respectively). Ten out of 75 patients in the inpatient group were admitted to ICU (intubated). Nine out of them lost their lives (the mortality rate in ICU-admitted patients was 90%). CONCLUSIONS: The lower mortality and severity of COVID-19 patients with higher 25(OH)D levels represented that this vitamin alleviates the severity of COVID-19.