Severe vitamin D deficiency is not related to SARS‑CoV‑2 infection but may increase mortality risk in hospitalized adults: a retrospective case–control study in an Arab Gulf country.

In a hospital-based study of 222 patients in Saudi Arabia, 25(OH)D deficiency is not associated with SARS-CoV-2 infection but may increase the risk for mortality in severely deficient cases [25(OH)D <12.5 nmol/l (<5 ng/ml)].

• Vitamin D deficiency [25(OH)D <50 nmol/l (<20 ng/ml)] was present in 75% of all patients.
• Serum 25(OH)D levels were significantly lower among SARS-CoV-2 positive than SARS-CoV-2 negative patients after adjusting for age, sex, and body mass index (BMI) [35.8±5 nmol/l (14.3±0.6 ng/ml) vs. 42.5±3.0 nmol/l (17±1.2 ng/ml)].
• Multivariate regression analysis revealed that significant predictors for SARS-CoV-2 positivity include age >60 years and pre-existing conditions (p < 0.05)
• Statistically significant predictors for mortality adjusted for covariates include male sex, chronic kidney disease and severe 25(OH)D deficiency, but at borderline significance

A total of 222 patients screened for SARS-CoV-2 and with measured 25(OH)D levels were admitted to the hospital in Riyadh, Saudi Arabia. One-hundred fifty patients (97 men, 64.7%; 53 women, 35.3%) were SARS-CoV-2 positive and 72 patients (38 men, 52.8%; 34 women, 47.2%) were SARS-CoV-2 negative. The mean age of the SARS-CoV-2 positive group was 55.5±15.8 years; the mean age of the SARS-CoV-2 negative group was 59.1±16.8 years.

• The lack of statistical significance in eliciting an association between severe vitamin D deficiency and mortality was likely due to low sample size.
• The findings only apply to hospitalized patients with pre-existing conditions and not the general community. Because 25(OH)D is a negative acute-phase reactant for both acute and chronic inflammatory-state diseases, most of the participants of this study were likely deficient given their age and pre-existing conditions, which are associated with chronic, low-grade systematic inflammation.
• Both the retrospective design and small number of COVID-19 tested patients made proper matching of the positive and negative cases difficult and led to mismatching for certain variables (e.g., pre-existing conditions).

The prevalence of vitamin D deficiency among hospitalized patients screened for SARS-CoV-2 in Saudi Arabia is remarkably high and is significantly lower in SARS-CoV-2-positive patients, even after adjusting for covariates known to influence vitamin D. Severe vitamin D deficiency, however, is not associated with SARS-CoV-2 infection and is more related to increased mortality risk.

• Included in this single-center retrospective study were a total of 222 patients screened for SARS-CoV-2 with measured 25(OH)D levels who were admitted at King Saud University Medical City-King Khalid University Hospital in Riyadh, Saudi Arabia from May–July 2020.
• Clinical information collected for all patients included demographics (age and sex), medical history (known cases of diabetes mellitus (DM), hypertension (HPN), cardiovascular disease (CVD), congestive heart failure (CHF), chronic kidney disease (CKD), stroke as well as smoking history) and medications taken prior to admission. Radiological findings, if available, were recorded.
• Height and weight were recorded, and body mass index (kg/m2) was calculated. Obesity was defined as having a BMI ≥ 30 kg/m².
• Non-fasting and fasting blood samples were obtained in all admitted patients. Serum 25(OH)D was assessed using CDC-approved vitamin D total assay kits (ADVIA Centaur, Siemens Healthcare GmbH, Erlangen, Germany) as certified by the Vitamin D Standardization-Certification Program.
• Vitamin D deficiency [25(OH)D < 50 nmol/l (<20 ng/ml)] and severe vitamin D deficiency [25(OH)D <12.5 nmol/l (<5 ng/ml)] were defined based on national and regional recommendations

Alguwaihes AM, Sabico S, Hasanato R, Al-Sofiani ME, Megdad M, Albader SS, Alsari MH, Alelayan A, Alyusuf EY, Alzahrani SH, Al-Daghri NM, Jammah AA. Severe vitamin D deficiency is not related to SARS-CoV-2 infection but may increase mortality risk in hospitalized adults: a retrospective case-control study in an Arab Gulf country. Aging Clin Exp Res. 2021 May;33(5):1415-1422. doi: 10.1007/s40520-021-01831-0. Epub 2021 Mar 31. PMID: 33788172; PMCID: PMC8009930.