Vitamin D sufficiency, a serum 25-hydroxyvitamin D at least 30 ng/mL reduced risk for adverse clinical outcomes in patients with COVID-19 infection

Abstract

Background: To investigate the association between serum 25-hydroxyvitamin D levels and its effect on adverse clinical outcomes, and parameters of immune function and mortality due to a SARS-CoV-2 infection.

Study design: The hospital data of 235 patients infected with COVID-19 were analyzed.

Results: Based on CDC criteria, among our study patients, 74% had severe COVID-19 infection and 32.8% were vitamin D sufficient. After adjusting for confounding factors, there was a significant association between vitamin D sufficiency and reduction in clinical severity, inpatient mortality serum levels of C-reactive protein (CRP) and an increase in lymphocyte percentage. Only 9.7% of patients older than 40 years who were vitamin D sufficient succumbed to the infection compared to 20% who had a circulating level of 25(OH)D< 30 ng/ml. The significant reduction in serum CRP, an inflammatory marker, along with increased lymphocytes percentage suggest that vitamin D sufficiency also may help modulate the immune response possibly by reducing risk for cytokine storm in response to this viral infection.

Conclusion: Therefore, it is recommended that improving vitamin D status in the general population and in particular hospitalized patients has a potential benefit in reducing the severity of morbidities and mortality associated with acquiring COVID-19.

Fig 1. The association between vitamin D status and inpatient mortality because of COVID-19.

A scatter plot relating mortality in patients with a serum 25(OH)D level. The red dots represent the inpatients who perished and the black dots represented the patients who have survived. The solid black line separates the patients with vitamin D deficiency/insufficiency (below the solid line) from the vitamin D sufficient patients (above the solid line). The number of red dots (inpatient mortality) above the solid line is significantly less compared to the dots below the line. Also, the trend of reducing inpatient mortality is continued for higher levels of serum 25(OH)D. The dotted line represents a serum level of 25(OH)D of 40 ng/mL. The mortality (red dots) is very rare in patients with serum 25(OH)D of at least 40ng/mL (above the dotted line). An evaluation of mortality in the patient population revealed that no one under the age of 40 years died as a result of being infected with COVID 19. However 16.3% of patients 40 years and older succumbed to the infection. Of the 206 patients who were 40 years and older, 20% had a blood level of 25(OH)D<30 ng/mL whereas only 9.7% who perished had a blood level of 25OH)D of at least 30 ng/mL(p = 0.04). Furthermore only 6.3% of the patients over 40 years of age died with a blood level of 25(OH)D of 40 ng/mL or higher.