Vitamin D as a predictor of negative outcomes in hospitalized COVID-19 patients: An observational study.

Introduction: Serum vitamin D deficiency is thought to be associated with worse clinical outcomes in COVID-19 patients.

Methods: This single-centre observational study evaluated the association between serum vitamin D levels and negative outcomes in hospitalized COVID-19 patients in Ukraine. We included hospitalized patients with COVID-19 confirmed by PCR and serum vitamin D measurement on admission. Patients were divided into two groups based on their serum vitamin D level: with adequate vitamin D (≥ 30 ng/ml) and with low vitamin D (<30 ng/ml). Outcomes such as death and the need for respiratory support were recorded.

Results: A total of 70 patients were included. The gender; severity of COVID-19; comorbidities such as hypertension, diabetes mellitus type 2, obesity; type of respiratory support, and the length of hospital stay did not differ in both groups. Patients with low serum vitamin D levels have higher C-reactive protein levels 26.14 mg/L [Q1, Q3: 16.61, 57.79] compared to another group 13.43 mg/L [Q1, Q3: 8.84, 27.58]. Low vitamin D level was associated with an increased risk of respiratory support need OR [Odds ratio] 2.925 [95% CI, 1.0839 to 7.8931]. However, after adjustment for age, gender, and common comorbidities, it did not remain significant. Vitamin D serum levels did not significantly differ in patients who died during hospitalization compared to those who survived.

Conclusion: The role of vitamin D as a sole predictor of mortality and respiratory support appears to be overestimated. Low vitamin D levels may have a greater impact on COVID-19 outcomes in hospitalized elderly patients with comorbidities.