3.1 Italian population
3.1.1 Suspect vs non-suspect COVID-19 pwMS.
One thousand and thirty-five from 1500 questionnaires were fulfilled (response rate =69%) in full and mailed back. Fifty-three pwMS fulfilled the questionnaires twice, therefore 106 responses were not included in the analysis. The Italian sample consisted of 929 pwMS. Fourteen (1,5%) fulfilled our criteria for the COVID-19-suspect case. Five were identified for reporting at least two symptoms. Nine pwMS were diagnosed based on the presence of at least one symptom and recent contact with a confirmed case of COVID-19 (by PCR analysis) or with a suspect case of COVID-19. Among the 14 pwMS identified as COVID-19 suspect cases, two (14,3%) pwMS reported symptoms worsening, and one of them a rapid worsening of symptoms. Table 1 reports demographic and clinical data of the whole Italian sample and the two subgroups, suspect and non-suspect COVID-19 pwMS.
There was no statistically significant difference in age, sex, lymphocyte count, previous DMTs, ongoing DMTs category, and prevalence of comorbidities between the two subgroups. Between the two subgroups, there was a significant difference between pwMS that reported to be on DMTs with very low/low risk of infection compared to those who reported being on moderate/high-risk DMTs (Table 1). 46.1% (n. 6 out of 13) of patients were on DMTs with moderate/high risk of infection and 53,7% (n. 7 out of 13) were on DMTs with very low/low risk of infection in the suspected COVID-19 group whereas in the non-suspected COVID-19 group only 21,9% (n. 169 out of 772) of patients were on DMTs with moderate/high risk of infection and 78,1% (n. 603 out of 772) were on DMTs with very low/low risk of infection (p-value<0.047). In the multivariable logistic regression model, no variables were independently associated with the likelihood of being in the COVID-19 suspect group.
3.1.2 Comparison between symptomatic vs asymptomatic suspect COVID-19 pwMS.
Forty-one out of 929 (4,4%) pwMS reported recent contact with a confirmed case of COVID-19 (by PCR analysis) or with a suspect case of COVID-19 and among them, 9 (21,9%) developed symptoms afterward. There was no statistically significant difference in sex, comorbidities, lymphocyte count, ongoing and previous DMTs category between pwMS with the suspect of COVID-19 who developed symptoms and those pwMS who did not (symptomatic vs asymptomatic). Instead, there was a higher likelihood to develop symptoms after contact with a confirmed or suspect case of COVID-19 in older (over the age of 50) than in younger patients. 55,5% (n. 5 out of 9) of pwMS in the group that developed symptoms and 15,6% (n. 5 out of 32) in the group that did not develop symptoms, were older than 50 years (p-value = 0,029). In the multivariable logistic regression model, no variables were independently associated with the likelihood of being in the group of patients that developed symptoms.
3.2 Iranian population
3.2.1 Suspect vs non-suspect COVID-19 pwMS.
1346/2000 questionnaires were fulfilled in full and mailed back (response rate = 67%). Sixty-six (4,9%) fulfilled our criteria for COVID-19-suspect case. Forty-seven (3.4%) were identified for reporting at least two symptoms. Nineteen pwMS were diagnosed based on the presence of at least one symptom and a history of recent contact with a confirmed case of COVID-19 (by PCR analysis) or with a suspect case of COVID-19. On 66 (4.9%) pwMS identified as suspect, 10 (15,1%) patients reported to have worsening symptoms but none of them reported a rapid worsening of symptoms. The demographic and clinical characteristics of the whole Iranian sample and the two subgroups, suspect and non-suspect COVID-19 pwMS, are summarized in Table 2. There was no statistically significant difference in age, sex, ongoing DMTs, previous DMTs, and comorbidities, except that for diabetes or heart disease, between the two groups. 15,15% (n. 10 out of 66) of patients in the COVID-19-suspect group reported diabetes or heart disease while only 3,8% (n. 49 out of 1280) of patients among non-suspect COVID-19 group reported diabetes or heart disease (p-value<0.001). In the multivariable logistic regression model diabetes/heart disease was independently associated with the likelihood of being in the COVID-19-suspect group (Table 3). Reporting diabetes or heart disease was associated with an increased likelihood of being in the COVID-19-suspect group (OR: 5,374; 95%CI: 2,470 – 11,985; p-value<0.001).
3.2.2 Comparison between symptomatic vs asymptomatic suspect COVID-19 pwMS.
Fifty-two out of 1346 (3,9%) pwMS reported recent contact with a confirmed case of COVID-19 (by PCR analysis) or with a suspect case of COVID-19 and among them, 19 (35,8%) developed symptoms afterward. There was no statistically significant difference in age, sex, previous DMTs, and comorbidities between patients that developed symptoms and patients that did not. The difference in the proportion of pwMS on different DMT categories between the two groups reached statistical significance (p-value = 0,045): 5.2% (n. 1 out of 19) of patients who developed symptoms were on depletive therapy with a moderate risk of infection vs 3,0% (n. 1 out of 33) of patients who did not were on depletive therapy with a moderate risk of infection. Patients treated with very low and low risk of infection therapy had a lower chance to develop symptoms after contact with a confirmed or a suspect case of COVID-19: the proportion of very low and low risk of infection medications-treated patients were 26,3% (n. 5 out of 19) and 5,3% (n. 1 out of 19) among patients that developed symptoms and 52,5% (n. 17 out of 33) and 18,2% (n. 6 out of 33), among patients that did not develop symptoms, respectively. In the multivariable logistic regression model, no variables were independently associated with the likelihood of being in the group of patients that developed symptoms.