A total of 841 patients with COVID-19 were admitted to Razi Hospital from February 2 to March 20, 2020, of which 153 patients were analyzed in this study who had laboratory documentation of a 25(OH) D level at the time of hospitalization. All patients had CT imaging findings typical of COVID-19 and a SARS-CoV-2 PCR-positive result. In total, 62.7% (n = 96) of the patients had a 25(OH) D level of less than 30 ng/mL and 37.25% (n = 57) had a 25(OH) D level of more than 30 ng/mL. To assess the role of vitamin D status in relation to the disease, socio-demographic features, comorbidity factors, and clinical outcomes, all data were classified into two subgroups based on 25(OH) D levels. The socio-demographics and comorbidities and clinical outcomes of COVID-19 patients are presented in Tables 1 and 2.
Table 1
Socio-demographics and Comorbidity of COVID-19 Patients Based on Vitamin D Level
| Total (N = 153) N (%) | 25(OH) D level ≥ 30 (N = 57) N (%) | 25(OH) D level ≤ 30 (N = 96) N (%) | P value | Odds ratio | 95% CI |
Socio-demographic characteristics |
Gender | Female | 66 (43.13) | 23(40.35) | 43 (44.79) | 0.6 | NA |
Male | 87(53.86) | 34(59.64) | 53 (55.2) |
Age > 50 | 98 (64.05) | 44 (77.19) | 54(56.25) | 0.009 | 2.63 | 1.258–5.509 |
Body mass index (BMI) | 29.909 ± 5.81 | 29.15 ± 5.71 | 29.92 ± 5.92 | 0.32 | NA |
Living area | Rural | 57(37.25) | 20(35.08) | 37 (38.54) | 0.73 | NA |
Urban | 96 (62.7) | 37(64.91) | 59(61.45) |
Preexisting comorbidities |
Diabetes | 41(26.79) | 19 (38.59) | 22 (22.91) | 0.18 | NA |
Hypertension | 44 (28.75) | 26 (45.61) | 18 (18.75) | 0.001 | 3.63 | 1.750–7.549 |
Cardiovascular disease | 30 (19.6) | 17(29.82) | 13(13.54) | 0.02 | 2.7 | 1.201–6.129 |
Dyslipidemia | 10 (6.53) | 1(1.75) | 9 (9.37) | 0.09 | NA |
Hypothyroidism | 9 (5.88) | 0 | 9 (9.37) | 0.02 | 0.906 | 0.850–0.966 |
Asthma | 6 (3.92) | 0 | 6 (6.25) | 0.08 | NA |
Malignancy | 3 (1.96) | 2 | 1 (1.04) | 0.55 | NA |
Chronic liver disease | 2 (1.3) | 1(1.75) | 1 (1.04) | 1 | NA |
Chronic Kidney Disease | 1 (0.65) | 1(1.75) | 0 | 0.37 | NA |
NA: not applicant; CI: confidence interval |
Based on age group patients were distributed in three groups including 35.94% (n = 55) less 50 years old, 34.64% (n = 53) in the range 50–65 years and 28.75% (n = 44) more than 65 years old respectively; 58.2% (n = 89) of patients were male, and 41.8% (n = 64) were female. Of the 98 patients who were 50 years and older, 56.25% had a blood level of 25(OH) D < 30 ng/mL (p = 0.009). There were no differences between the two groups (patients with serum level 25(OH) D level ≥ 30 and patients with serum level 25(OH) D level ≤ 30) in regards to gender and living area. Most of the patients had multiple underlying disorders. The most common underlying illnesses were hypertension 26.8% (n = 44), diabetes 26.8% (n = 41), cardiovascular disease19.6% (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. In total, 49% (n = 75) of patients suffered from at least one underlying disease. Significant differences between the two groups were noted to be preexisting comorbidities such as hypertension, cardiovascular disease, and hypothyroidism (p < 0.05). Hypertension (17/30) and cardiovascular disease (13/30) were mostly noted among patients with blood level 25(OH) D level ≥ 30 ng/mL, while hypothyroidism was only seen in patients with blood level 25(OH) D level ≤ 30 ng/mL.
Table 2
The COVID-19 Clinical Outcomes of Patients Based on Vitamin D Level
Outcomes of patients | Total (N = 153) N (%) | 25(OH) D level ≥ 30 (N = 57) N (%) | 25(OH) D level ≤ 30 (N = 96) N (%) | P value |
Duration of hospitalization (days) Mean ± SD | 6.3 ± 4.12 | 6.36 ± 4.35 | 6.25 ± 4.01 | 0.8 |
Bilateral lung involvement | 28(17.64) | 10(17.54) | 18(17.7) | 0.3 |
ICU admission | 10(6.53) | 3(5.26) | 7(7.29) | 0.5 |
Invasive mechanical ventilator use | 3(1.96) | 1(1.75) | 2(2.083) | 1 |
Non-invasive ventilation | 15(9.08) | 5(8.77) | 10(10.41) | 1 |
Severity of disease | Mild | 85(55.6) | 27 (47.36) | 58(60.41) | 0.08 |
Moderate | 51(33.3) | 21(36.84) | 30(31.25) |
Severe | 17(11.1) | 9(15.78) | 8(8.33) |
Death | 5(3.26) | 2(3.57) | 3(3.12) | 1 |
The average hospitalization stay of patients were 6.3 ± 4.12 days. Bilateral lung involvement was seen in 17.64% of patients. In total, 6.53% of patients were admitted to the ICU. Invasive mechanical ventilator was utilized for 1.96% of patients while 9.08% of patients were under non-invasive ventilation. Based on severity of disease, 55.6% of patients were categorized into the mild form of COVID-19 disease, while 33.3% and 11.1% experienced the moderate and severe / critical forms of COVID-19, respectively. Overall, 3.26% of patients involved expired. 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.
Ordinal logistic regression showed that male patients (OR 2.5, 95% CI (1.241, 5.301), P = 0.011) and patients with diabetes (OR 3.98, 95% CI (1.34, 11.86), P = 0.013) experienced the severe form of COVID-19 infection more often than other patients. Multiple logistic regression showed that patients with cardiovascular disease were more at risk of requiring non-invasive ventilation (OR 4.37, CI (1.44, 13.26), P = 0.009). There was no significant association between other effective predisposing risk factors such as socio-demographic characteristics and preexisting comorbidities on the outcome of COVID-19.