The evaluation of impacts of serum levels of vitamin D on severity of COVID-19 infection in hospitalized patients in Imam Reza hospital from the beginning of pandemic

Abstract

Some studies have shown that there is a relationship between the serum level of some factors and the severity of the corona disease; Vitamin D can be mentioned among these factors. The aim of this study is the evaluation of impacts of serum levels of vitamin D on severity of COVID-19 infection in hospitalized patients in Imam Reza hospital from the beginning of pandemic. Materials and Methods: This research was a retrospective cohort study. The target population of the study was the patients admitted to the Covid ward of Imam Reza Hospital in Tabriz since the beginning of the pandemic. Patients with COVID-19 were confirmed using RT-PCR in the reference laboratory of East Azarbaijan province (referred to this center) or radiographic manifestations. Due to the fact that the new strain of corona virus (Omicron) can be diagnosed with clinical manifestations, this group was also included in the study. The required sample size was determined to be 326 people. Sampling was done by census method. Using the checklist method, information was extracted from the patients' files and analyzed. In this study, patients' demographic information including vitamin D serum level, body temperature, length of hospitalization, need for ventilator, need for intensive care unit, blood oxygen level, blood pressure, age, gender, body mass index and vaccination information were extracted from the patients' files. The incidence of death among the studied population was also investigated. The severity of the covid disease was measured by the blood oxygen level, the need for a ventilator, body temperature and the length of hospitalization. Results: In this study, the mean (standard deviation) level of vitamin D in the subjects was 28.13 (±16.3) (ng/ml). 215 cases (66.0%) of these people had a history of vaccination. The severity of the covid disease in the studied subjects was mild in 12 cases (3.7 percent), moderate in 132 cases (40.5 percent), severe in 145 cases (44.5%), and very severe in 37 cases (11.3%). The median (first and third quartile) length of hospitalization in these people was 7.0 (5.0 - 14.0) days. 161 cases (49.4%) of these people needed a ventilator and needed Intensive Care Unit (ICU). Finally, 97 cases (29.8%) of these people died. In this study, among the subgroups of the severity of the Covid disease in the studied subjects, the serum level of vitamin D was significantly higher in patients with mild severity compared to patients with very severe severity (MD=14.85; P=0.027), patients with moderate severity compared to patients with severe severity (MD=5.34; P=0.029) and very severe (MD=11.66; P=0.001). Among the demographic characteristics, blood pressure and vaccination, none of the variables of gender, age, BMI, systolic and diastolic blood pressure and history of vaccination were observed statistically significant relationship with vitamin D serum level in all the studied covid patients (P>0.05).