Participants and study protocol
This epidemiological cross-sectional-analytical study was conducted at Abadan University of Medical Sciences, Abadan, Khuzestan Province, Iran. With the coordination between the vice-chancellor for education and the vice-chancellor for health of Abadan University of Medical Sciences, a list of outpatients was obtained from the deputy minister of health. Patients on the list had been referred to 16-hour comprehensive health centers in Abadan for COVID-19 PCR testing between the beginning of April and the end of July 2020 and had definitive (negative/ positive) PCR results.
By telephone contact with these outpatients, those who met the criteria for inclusion (all ages, male and female gender) in the study and provided informed consent to participate were selected and assigned to two groups: negative and positive PCR (N= 52 in each group).
The study protocol was approved by the Ethics Committee of Abadan University of Medical Sciences (Ethics Code: IR.ABADANUMS.REC. 1399.079) following the Declaration of Helsinki for medical research involving human subjects. Outpatients with known hypothalamic, pituitary, adrenal, or severe hepatic diseases—as well as those on corticosteroid treatment or other medications affecting adrenal function—in the preceding three months, were excluded. Also, those who had known RAAS disorders or were on any medications which interfere with the activity of this system during the three last months were excluded. Also, pregnancy and lactation in women, unclear PCR test results, PCR testing for the second time, smoking during the test period, high-risk jobs including healthcare staff and public transport drivers (for the control group) were grounds for exclusion, as were any other circumstances that the researcher did not consider to justify the participation of individuals.
With prior coordination, the participants were referred to Imam Khomeini Health Center. All participants were asked to go to the Imam Khomeini Center in a fasting state between 7:00 a.m. and 9:00 a.m. Patients’ medical histories were retrospectively reviewed, and their demographic information (age and sex) and clinical data (respiratory rate, pulse rate, SPO2) were collected. Also, the participant’s clinical symptoms were recorded in four groups of symptoms: general (fever, fatigue, night sweats, shivering, and asthenia), respiratory (cough and dyspnea), gastrointestinal (nausea, constipation, and diarrhea), and neurologic (muscle/joint pain, loss of taste/smell, headache)(11) via self-reports.
The participants were then referred to the Abadan Private Health Laboratory, where a blood sample was collected from each person and stored for biochemical tests. Routine laboratory investigations were performed within the first 24 hours after laboratory admission. These included blood groupings using commercially prepared monoclonal anti-A, anti-B, and anti-D antisera (Agappe Diagnostics Ltd., India), assessment of serum levels of cortisol (Cortisol ELIZA Kit; Monobind Inc.), and serum levels of aldosterone (Aldosterone ELIZA Kit; Monobind Inc.). The day of referral to Imam Khomeini Health Center was considered the first day of the study for each person. The clinical symptoms of PCR-positive outpatients were followed up with and recorded over 28 days (in one-week intervals) by telephone.