Risk factors associated with the severity of COVID-19 in patients with multiple sclerosis (MS) begin to be identified from several cohort studies. Disease modifying therapies (DMTs) may modify the risk of developing a severe COVID-19 infection, beside identified risk factors such as age and comorbidities.
The objective was to describe the clinical characteristics and outcomes in patients with COVID-19 and to identify the factors associated with COVID-19 severity.
This multicenter, retrospective, observational cohort study (COVISEP registry, NCT04355611) included patients with MS presenting with a confirmed or highly suspected diagnosis of COVID-19 between March 1, 2020 and July 14, 2020. The main outcome was COVID-19 severity assessed on a 7-point ordinal scale (ranging from 1: not hospitalized, no limitations on activities, to 7: death; cutoff at 3: hospitalized, not requiring supplemental oxygen). We collected demographics, neurological history, Expanded Disability Severity Score (EDSS), comorbidities, COVID-19 characteristics and outcome. Univariate and multivariate logistic regression models were used to estimate the influence of collected variables on COVID-19 outcome.
A total of 405 patients (mean age: 44.7 years, female/male: 293/112, mean disease duration: 13.4 years) were analyzed. Seventy-eight patients (19.3%) had a COVID-19 severity score ≥ 3, and 12 patients (3.0%) died from COVID-19. Median EDSS was 2.0 (range: 0-9.5), 326 patients (80.5%) were on DMT. There was a higher proportion of patients with COVID-19 severity score ≥ 3 among patients with no DMT relative to patients on DMTs (39.2% versus 14.4%, p<0.001). Multivariate logistic regression models determined that age (OR for 10 years: 1.8, 95% CI: 1.4-2.4), EDSS (OR for EDSS ≥ 6: 4.5, 95% CI: 2.0-10.0) were independent risk factors for COVID-19 severity score ≥ 3 (hospitalization or higher severity) while immunomodulatory treatment (interferon or glatiramer acetate) was associated with lower risk of COVID-19 severity score ≥ 3 (OR: 0.2, 95% CI: 0.05-0.8). EDSS was associated with the highest variability of COVID-19 severe outcome (R2= 0.18), followed by age (R2= 0.06) and immunomodulatory treatment (R2= 0.02).
EDSS and age were independent risk factors of severe COVID-19, while exposure to immunomodulatory DMTs (interferon and glatiramer acetate) were independently associated with lower COVID-19 severity. We did not find an association between other DMTs exposure (including immunosuppressive therapies) and COVID-19 severity. The identification of these risk factors should provide the rationale for an individual strategy regarding clinical management of MS patients during the COVID-19 pandemic.