Association between 25-hydroxyvitamin D levels and COVID-19 severity

Abstract

Background and aims: Despite reports on the impact of vitamin D status on coronavirus disease 2019 (COVID-19) severity, the association between low vitamin D status and severe COVID-19 remains unclear. Moreover, researchers have not determined the aforementioned association in Japanese patients. This study aimed to investigate the association between 25-hydroxyvitamin D [25(OH)D] levels and COVID-19 severity in Japanese patients.

Methods: This retrospective observational study included 117 consecutive patients with COVID-19 admitted to the Kobe City Medical Center General Hospital between October 01, 2020, and January 31, 2021. We measured the serum 25(OH)D levels using blood specimens collected within 5 days of hospital admission using liquid chromatography-tandem mass spectrometry.

Results: There were 21 (17.9%), 73 (62.4%), 19 (16.2%) and 4 (3.4%) patients with severe deficiency (<10 ng/mL), deficiency (10-<20 ng/mL), insufficiency (20-<30 ng/mL), and sufficiency (≥30 ng/mL) of vitamin D, respectively. In univariate logistic regression analyses, lower serum 25(OH)D levels [odds ratio (OR) 1.18 per 1 ng/mL decrease, 95% confidence interval (CI) 1.04-1.33, p = 0.007] were significantly associated with invasive mechanical ventilation (IMV) or death. In a multivariate logistic regression analysis, low serum 25(OH)D levels [OR 1.22 per 1 ng/mL decrease, 95% CI 1.06-1.40, p = 0.005] were significantly associated with IMV or death. The cut-off value of serum 25(OH)D levels was 10.4 ng/mL, calculated by the receiver operating characteristic curve to detect the requirement for IMV or death.

Conclusions: To the best of our knowledge, this is the first study to assess the association between vitamin D status and COVID-19 severity in Japanese patients. Low serum 25(OH)D level was detected as an independent risk factor for severe COVID-19 among Japanese patients.

Keywords: COVID-19; Japanese; SARS-CoV-2; Vitamin D.

Fig. 1

Incidence of (A) receiving oxygen therapy and (B) receiving invasive mechanical ventilation or death based on serum 25(OH)D levels. The rate of (A) receiving oxygen therapy and, (B) receiving invasive mechanical ventilation or death are compared by serum 25(OH)D levels (severe vitamin D deficiency [<10 ng/mL], deficiency [10–<20 ng/mL], insufficiency [20–<30 ng/mL] and sufficiency [≥30 ng/mL]). The Cochran-Armitage trend test displays a trend in reduced rates of (A) receiving oxygen therapy and, (B) receiving IMV or death with increased serum 25(OH)D levels (p = 0.001 and p = 0.017, respectively). IMV, invasive mechanical ventilation; 25(OH)D, 25-hydroxyvitamin D.

Fig. 2

Area under ROC curves obtained by the univariate logistic regression analysis of serum 25(OH)D levels for (A) receiving oxygen therapy and, (B) receiving invasive mechanical ventilation or death. ROC, receiver operating characteristic; 25(OH)D, 25-hydroxyvitamin D.