Abstract: nutrients Article Vitamin D Deficiency and Outcome of COVID-19 Patients Aleksandar Radujkovic 1 , Theresa Hippchen 2 , Shilpa Tiwari-Heckler 2 , Saida Dreher 2 , Monica Boxberger 2 and Uta Merle 2, * 1 2 * Department of Internal Medicine V, University of Heidelberg, 69121 Heidelberg, Germany; aleksandar.radujkovic@med.uni-heidelberg.de Department of Internal Medicine IV, University of Heidelberg, 69121 Heidelberg, Germany; theresa.hippchen@med.uni-heidelberg.de (T.H.); shilpa.tiwari-heckler@med.uni-heidelberg.de (S.T.-H.); saida.dreher@med.uni-heidelberg.de (S.D.); monica.boxberger@med.uni-heidelberg.de (M.B.) Correspondence: uta.merle@med.uni-heidelberg.de; Tel.: +49-6221-568705 Received: 9 August 2020; Accepted: 9 September 2020; Published: 10 September 2020



 Abstract: Infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) poses an enormous challenge to health care systems throughout the world. Without causal treatment, identification of modifiable prognostic factors may help to improve outcomes. To explore possible associations of vitamin D (VitD) status with disease severity and survival, we studied 185 patients diagnosed with coronavirus disease 2019 (COVID-19) and treated at our center. VitD status at first presentation was assessed retrospectively using accredited laboratory methods. VitD deficiency was defined as serum total 25-hydroxyvitamin D level < 12 ng/mL (<30 nM). Primary endpoint was severe course of disease (i.e., need for invasive mechanical ventilation and/or death, IMV/D). Within a median observation period of 66 days (range 2–92), 23 patients required IMV. A total of 28 patients had IMV/D, including 16 deaths. Ninety-three (50%) patients required hospitalization (inpatient subgroup). A total of 41 (22%) patients were VitD deficient. When adjusted for age, gender, and comorbidities, VitD deficiency was associated with higher risk of IMV/D and death (HR 6.12, 95% CI 2.79–13.42, p < 0.001 and HR 14.73, 95% CI 4.16–52.19, p < 0.001, respectively). Similar correlations were observed in the inpatient subgroup. Our study demonstrates an association between VitD deficiency and severity/mortality of COVID-19, highlighting the need for interventional studies on VitD supplementation in SARS-CoV-2 infected individuals. Keywords: vitamin D; SARS-CoV-2; COVID-19; outcome; severity; retrospective