Patients with COVID-19 pneumonia with 25(OH)D levels lower than 12 ng/ml are at  increased risk of death.

Serum level of 25(OH) D is an independent risk factor of mortality. In addition, a serum 25(OH) D level <12 ng/ml at the time of admission was a good indicator of morbidity and mortality in patients with COVID-19 in this study, and was associated with a 11% increased mortality rate compared to patients with a serum level above 12 ng/ml.

• Low serum 25(OH) D was common, with 25(OH) D levels in 80% of patients being either insufficient or deficient according to existing guidelines (i.e., 25[OH] D <30 ng/ml). 
• There was lower 25(OH) D levels, platelet counts and oxygen saturation, and higher age, CRP, viral load, white blood cells, neutrophils, and Charlson comorbidity index in nonsurvivors than in survivors (all p <0.005). 
• Arterial hypertension, chronic kidney disease, diabetes mellitus with complications, chronic heart failure, and chronic kidney disease were more prevalent in nonsurvivors compared with survivors (p <0.05). 
• There was no difference in sex, body mass index (BMI), liver cirrhosis prevalence, lymphocyte count, PCT, D-Dimer, vitamin D use before hospitalization, and IL-6 in survivors compared with nonsurvivors. 
• In multivariate linear regression analysis, serum level of 25(OH) D remained independently associated with in-hospital mortality (p = 0.0398).  
• Age, CRP, blood oxygen level saturation, platelet count, Charlson comorbidity index, and BMI were significantly and independently associated with mortality (all p <0.05). 
• Mortality was 11% higher in the group with vitamin D <12 ng/ml (∼55% vs ∼44%; p <0.05). 

357 (198 male 159 female) patients with COVID-19 admitted to the hospital between 9/1/20 and 4/30/21.

• The researchers were not able to repeatedly assess serum levels of 25(OH) D during the disease, which would have potentially better established the evolving relationship between levels of inflammatory biomarkers and 25(OH) D.  
• They did not know the pre-existing vitamin D status of the patients in the study cohort. Therefore, the possibility of so-called reverse causality to explain the relationship of 25(OH) D with COVID-19, i.e., that a more severe disease produces greater 25(OH) D reduction must still be considered. 
• Vitamin D supplementation during hospitalization could in fact influence mortality. All of the patients were supplemented with vitamin D according to the treatment protocol at the institution, regardless of baseline 25(OH) D serum levels (loading dose: 30 000 IU of cholecalciferol per day for the first 3 days, followed by 7500 IU cholecalciferol per day). The researchers did not have a control group of patients without supplementation. 

“In conclusion, this study shows that 25(OH) D insufficiency or deficiency is prevalent among acutely ill patients hospitalized for COVID-19 pneumonia. Importantly, the serum level of 25(OH) D is an independent risk factor of mortality. In addition, a serum 25(OH) D level <12 ng/ml at the time of admission seems to be a good indicator of morbidity and mortality in patients with COVID-19 and is associated with a 11% increased mortality rate than patients with a serum level above 12 ng/ml. According to these results, routine 25(OH) D assessment at admission could be relevant for risk stratification and planning for treatment strategy in patients with COVID-19.” 

• A single center longitudinal cohort study of 357 patients with COVID-19.  
• Subjects were monitored until discharge or in-hospital death (47% died of COVID-19).  
• At admission, severity parameters (C-reactive protein [CRP], IL-6, Charlson comorbidity index, etc.) were assessed. These parameters were compared to a 25(OH)D levels threshold of 12 ng/ml, where values below 12 ng/ml were considered absolute vitamin D deficiency. 

Smaha J, Kužma M, Brázdilová K, Nachtmann S, Jankovský M, Pastírová K, Gažová A, Jackuliak P, Killinger Z, Kyselovič J, Koller T, Binkley N, Payer J. Patients with COVID-19 pneumonia with 25(OH)D levels lower than 12 ng/ml are at increased risk of death. Int J Infect Dis. 2022 Mar;116:313-318. doi: 10.1016/j.ijid.2022.01.044. Epub 2022 Jan 22. PMID: 35077879; PMCID: PMC8783398.