Vitamin D insufficiency as a potential culprit in critical COVID-19 patients.

Munshi, Ruhul; Hussein, Mohammad H; Toraih, Eman A; Elshazli, Rami M; Jardak, Christina; Sultana, Nasrin; Youssef, Mohanad R; Omar, Mahmoud; Attia, Abdallah S; Fawzy, Manal S; Killackey, Mary; Kandil, Emad; Duchesne, Juan

BACKGROUND As an immune modulator, vitamin D has been implicated in the Coronavirus disease-2019 (COVID-19) outcome. We aim to systematically explore the association of vitamin D serum levels with COVID-19 severity and prognosis. METHODS The standardized mean difference (SMD) or odds ratio and 95% confidence interval (CI) were applied to estimate pooled results from seven studies. The prognostic performance of vitamin D serum levels for predicting adverse outcomes with detection of the best cutoff threshold was determined by ROC curve analysis. Decision tree analysis by combining vitamin D levels and clinical features was applied to predict severity in COVID-19 patients. RESULTS Mean vitamin D serum level of 1,368 patients, was 22.9 nmol/L (21.9-23.8). Significant heterogeneity was found (I2 = 99.9%, P< 0.001). Patients with poor prognosis (N=634) had significantly lower serum levels of vitamin D compared to those with good prognosis (N=669), representing an adjusted standardized mean difference of -5.12 (95% Cl= -9.14 to -1.10, P = 0.012). CONCLUSION Serum vitamin D levels could be implicated in the COVID-19 prognosis. Diagnosis of vitamin D deficiency could be a helpful adjunct in assessing patients' potential of developing severe COVID-19. Appropriate preventative and/or therapeutic intervention may improve COVID-19 outcomes. This article is protected by copyright. All rights reserved.