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COVID-19 Disease Severity and Death in Relation to Vitamin D Status among SARS-CoV-2-Positive UAE Residents.
Take Home Message
In a multicenter observational study of 464 COVID-19 patients living in the United Arab Emirates conducted between August 2020 to February 2021, serum 25(OH)D levels <12 ng/mL (30 nmol/l) were strongly associated with COVID-19 severity and mortality.
- The main comorbidities, Type-2 diabetes mellitus (32.8%), cardiac disease (11.6%) and renal disease (8.8%), were more prevalent among patients in the severe category.
- Patients who had severe infection were significantly older and more obese.
- A total of 26 (5.6%) of 464 subjects died.
- A total of 155 (33.4%) patients were vitamin D sufficient, whereas 182 (39.2%) were deficient and 127 (27.4%) were severely deficient.
- Serum 25(OH)D levels of <12 ng/mL (<30 nmol/l) when adjusted for age, sex and smoking (OR = 1.79 (95% CI, 1.21, 2.64); p = 0.003) and age, sex, smoking and comorbidities (OR = 1.76 (95% CI, 1.19, 2.61); p = 0.005) were strongly associated with severity of COVID-19.
Four-hundred sixty-four patients (372 men, 80.2%; 92 women, 19.8%) living in the United Arab Emirates (UAE) with a positive reverse transcriptase (RT)-PCR test for SARS-CoV-2 were enrolled in the study and included for data analysis. The mean age was 47±15 years.
Things to Keep in Mind
- The observational design of the study cannot substantiate causality between serum vitamin D levels and severity of COVID-19 disease.
- No control group has been included in the study. A similar vitamin D deficiency may be expected in subjects with baseline characteristics similar to the COVID-19 patients.
- Significantly more men (80.2%) were enrolled in the study than women (19.8%).
- The number of deaths in the study is small. Examining a larger sample to include more mortalities could offer more conclusive results about the relationship between vitamin D status and deaths due to COVID-19 infection in the UAE.
- The socioeconomic status for all participants was not assessed but could have impacted the dietary habits and availability of fortified foods, which in turn could have affected vitamin D status. Data regarding supplement use and sun exposure were not recorded.
- The optimal concentration of serum 25(OH)D for overall health remains controversial and agreement on cutoff values for sufficiency and deficiency by the medical and scientific communities would harmonize research.
Our data showed that serum 25(OH)D levels <12 ng/mL are strongly associated with COVID-19 severity and mortality among a sample of affected people in the UAE. Such findings suggest important implications that vitamin D supplementation could help reduce the severity of COVID-19 disease and risk of infection. Further larger observational studies and RCTs are needed to furnish a comprehensive picture about the link between vitamin D and COVID-19 severity and death among the UAE population.
- This was a multicenter observational study of 522 COVID-19 positive patients in Abu Dhabi and Dubai, UAE conducted from August 2020 to February 2021. Due to missing body mass index values (BMI), only 464 patients were included for data analysis.
- The diagnosis of COVID-19 was confirmed by RT-PCR of viral RNA extracted from nasal swabs.
- Demographic, clinical and outcome data of COVID-19 patients were gathered from questionnaires administered by medical staff at the hospital.
- Clinical assessments of participants included determining the severity (mild, moderate, or severe) and diagnosis of pneumonia, confirmed using a chest X-ray. Although participants who presented with mild or no symptoms did not require hospitalization, they were included in the study because they tested positive for SARS-CoV-2. The moderate group had symptoms such as fever, cough, and pneumonia, requiring hospitalization. The severe group presented with critical clinical features, such as high temperature, cough, pneumonia, and shortness of breath, requiring intensive care.
- Blood samples were collected at recruitment. To assess vitamin D status, the levels of total 25(OH)D were determined using automated electrochemiluminescence. Patients were grouped into three categories of serum 25(OH)D levels: severely deficient, <12 ng/mL (<30 nmol/l); deficient, 12–20 ng/mL (30-50 nmol/l); or sufficient, ³20 ng/mL (³50 nmol/l).
- The endpoint variable for COVID-19 severity was defined as admission to the intensive care unit, requirement of mechanical ventilation, or death.
- Predictors for severity of infection were determined using multivariate ordered logistic regression. To adjust for confounding factors, two models were used: model 1 adjusted for age, sex and smoking; and model 2 adjusted for age, sex, smoking and comorbidities.