Lack of association between vitamin D insufficiency and clinical outcomes of patients with COVID-19 infection.

In a cross-sectional retrospective study of 153 hospitalized patients in Iran, sufficient vitamin D levels (³30 ng/ml or 75 nmol/l) were not found to be protective against adverse clinical outcomes in patients infected with COVID-19. Chronic disorders in COVID-19 patients were found to have greater relevance than vitamin D levels in determining the adverse outcomes of the infection.

• The mean vitamin D level of the patients was 27.19±17 ng/mL (70±50.4 nmol/l).
• In total, 62.7% (n = 96) of the patients had a 25(OH) D level of < 30 ng/mL (<75 nmol/l) and 37.25% (n = 57) had a 25(OH) D level of > 30 ng/mL (nmol/l).
• Approximately, 49% (n = 75) of the patients suffered from at least one underlying disease. The most common underlying illnesses were hypertension 26.8% (n = 44), diabetes 26.8% (n = 41), cardiovascular disease 19.6% (n = 30), dyslipidemia 6.5% (n = 10), hypothyroidism 5.9% (n = 9), asthma 5.9% (n = 9), malignancy 1.96% (n = 3) and chronic liver disease 1.3% (n = 2), respectively.
• The average hospitalization stay of patients was 6.3±12 days. Bilateral lung involvement was seen in 17.64% (n = 28) of patients. In total, 6.53% (n = 10) of patients were admitted to the ICU. Invasive mechanical ventilator was utilized for 1.96% (n = 3) of patients while 9.08% (n = 15) of patients were under non-invasive ventilation. Based on severity of disease, 41.7% (n = 72) of patients were categorized into the mild form of COVID-19 disease, while 41.2 (n = 63) and 11.8% (n = 18) experienced the moderate and severe / critical forms of COVID-19, respectively. Overall, 3.26% (n = 5) of patients died.
• In univariate and multivariate analyses, vitamin D sufficiency was not associated with a statistically significant lower risk of adverse clinical outcomes of COVID-19 such as duration of hospitalization, lung involvement, ICU admission, invasive and non-invasive ventilation, severity of disease, or death.

One hundred fifty-three COVID-19 patients (87 men, 56.9%; 66 women, 43.1%) >18 years in Iran and who had real-time reverse transcriptase-PCR confirmation of SARS-CoV-2 infection and laboratory documentation of 25(OH)D level at the time of hospitalization.

• The observational design of the study cannot substantiate causality between serum vitamin D levels and severity of COVID-19 disease.
• Only patients who had documented vitamin D levels were included in the study.
• The sample size was small and some confounding factors, such as smoking and socioeconomic status, that may impact COVID-19 severity were not recorded for most patients.

Sufficient vitamin D levels (³30 ng/ml or 75 nmol/l) were not found to be protective against adverse clinical outcomes in patients infected with COVID-19. Chronic disorders in COVID-19 patients were found to have greater relevance than vitamin D levels in determining the adverse outcomes of the infection.

• This cross-sectional retrospective study analyzed the vitamin D levels of COVID-19 patients > 18 years who were admitted to Razi Hospital (Mazandaran province in northern Iran) from February to March 2020. Overall, a cutoff of ³30 ng/mL (75 nmol/l) was used to define vitamin D sufficiency.
• Definitions of COVID-19 severity were based on the World Health Organization COVID-19 clinical management guideline.
• Data such as demographic information (age, sex, body mass index [BMI], and living area), medical history, comorbidities, and diagnostic data of the patients, including vitamin D levels and patient outcomes were extracted from medical files.
• The following outcomes were measured: duration of hospitalization, lung involvement, ICU admission, invasive and non-invasive mechanical ventilator use, severity of disease, and in-hospital mortality.

Davoudi A, Najafi N, Aarabi M, Tayebi A, Nikaeen R, Izadyar H, Salar Z, Delavarian L, Vaseghi N, Daftarian Z, Ahangarkani F. Lack of association between vitamin D insufficiency and clinical outcomes of patients with COVID-19 infection. BMC Infect Dis. 2021 May 18;21(1):450. doi: 10.1186/s12879-021-06168-7. PMID: 34006228; PMCID: PMC8130780.