Immunosuppressive Therapy as Risk Factor for Severe SARS-CoV-2 Infection in Myasthenia Gravis

ABSTRACT

Importance Patients with myasthenia gravis (MG) and IST are potentially at increased risk for poor COVID-19 outcome. Objective: To determine whether immunosuppressive therapy (IST) compared to no IST is associated with a higher risk for, first, a symptomatic SARS-CoV-2 infection and, second, a more severe COVID-19 disease course as measured by hospitalization rate and death. Design, setting, and participants: The present study included all available MG patients from the German myasthenia gravis registry, which is a nationwide registry conducted by expert centers since February 2019 (German Clinical Trials Registry DRKS-ID 00024099). Main outcomes and measures: Between May 2020 and June 2021, data were collected on demographics, disease duration, comorbidities, preexistent IST including standard (corticosteroids, azathioprine, mycophenolate mofetil, methotrexate, cyclosporine) and escalation (rituximab, eculizumab) IST, thymectomy, COVID-19 characteristics, and outcomes. COVID-19 was diagnosed with a nasopharyngeal swab by polymerase-chain-reaction. Multiple binary logistic regression models and generalized estimation equation regression models based on matched SARS-CoV-2 infected to non-infected patients were used to estimate the association of IST with SARS-CoV-2 infection. Multiple binary logistic regression models were used to assess the association of IST with outcome of COVID-19 in MG patients. Results: Of 1388 MG patients, 95 (7%) MG patients with a mean age of 58 (SD 18) and median disease duration of 65 months (IQR 27-126) presented with COVID-19. Among them, 39 patients (41%) were male, and 76 (80%) received IST at the time of infection. There were 32 patients (34%) admitted to hospital due to COVID-19, 12 (13%) to the intensive care unit, and a total of 11 patients (12%) died. IST was a risk factor for hospitalization and death in the group of COVID-19 affected MG patients (adjusted odds ratio [OR] 3.04, 95% confi- dence interval [CI] = 1.02-9.06, p=0.046), but not for symptomatic SARS-CoV-2 infection itself in the whole group of MG patients. Conclusions and relevance In MG patients, preexistent IST was a factor for a severe disease course of COVID-19 but not for the risk for SARS-CoV-2 infection. These data support the consequent implementation of effective strategies to prevent COVID- 19 in this high-risk group.