Vitamin D Supplementation Improves Serological Parameters and Recovery Outcomes in COVID-19 Patients

This study aimed to investigate the effects of vitamin D on serological, etiological, and imaging indicators in patients with Coronavirus Disease 2019 (COVID-19), exploring new strategies for its prevention and treatment.

In this retrospective observational study, 300 COVID-19 patients admitted between January 2022 and March 2023 were enrolled from a public health center and our hospital. Participants were stratified into standard treatment (n=150) and vitamin D supplementation (n=150) groups. Outcomes included clinical recovery and improvements in laboratory, etiological, and imaging findings.

No significant intergroup differences were observed at baseline in demographic or laboratory parameters, including white blood cell (WBC), neutrophil (NEUT), lymphocyte (LYM), interleukin (IL)-6, c-reactive protein (CRP), procalcitonin (PCT), and serum calcium (P > 0.05). Both groups exhibited subnormal 25(OH)D levels initially. After adjusting for age, sex, hypertension, diabetes, and cardiovascular and cerebrovascular diseases, multivariable linear regression analyses indicated that the vitamin D group showed significant increases in 25(OH)D and serum calcium, while the standard treatment group exhibited only a mild increase in 25(OH)D with no significant change in serum calcium after treatment. Both groups showed decreases in WBC, NEUT, IL-6, CRP, and PCT, and increases in LYM after treatment. Compared with the standard group, the vitamin D group had greater improvements in NEUT, LYM, 25(OH)D, and serum calcium (P < 0.05), and more pronounced reductions in IL-6 and CRP (P < 0.05). Symptom resolution and viral clearance times were significantly shorter in the vitamin D group (P < 0.05), and imaging improvements were more evident (P < 0.05).

Supplementation with vitamin D, in addition to standard treatment, improves inflammatory markers, shortens the disease course, and is associated with radiographic improvement in COVID-19 patients.