MG treatments should continue during COVID-19 infection: Study
Continuing treatments actually seen to reduce later MG exacerbation risk
The use of myasthenia gravis (MG) treatments did not increase COVID-19 infection risk or severity, according to a new study of Chinese patients with both generalized myasthenia gravis (gMG) and ocular types of MG.
In fact, continuing treatment with nonspecific nonsteroidal immunosuppressants and antibody therapies during infection was seen to reduce the risk of MG exacerbation — experiencing additional or worsening symptoms — after COVID-19 infection, according to the researchers.
Patients with gMG who had more severe symptoms before COVID-19 infection were found to be at higher risk for experiencing both severe COVID-19 infection and exacerbation of MG symptoms within a month of contracting the virus.
“These results are important for establishing evidence-based guidelines for managing patients with MG during the COVID-19 pandemic,” the researchers wrote in “Clinical features of COVID-19 infection in patients with myasthenia gravis: a real-world retrospective study.” The study was published in the journal Frontiers of Public Health.
Investigating the real-world relationship between MG and COVID-19
MG is an autoimmune condition that occurs when the immune system attacks important proteins required for nerve-muscle communication, causing symptoms like progressive muscle weakness. While such symptoms can occur in muscles throughout the body, respiratory muscle weakness can lead to dangerous difficulties with breathing or MG crises.
Signs of COVID-19, meanwhile, “are diverse but typically include fever, cough [and] respiratory symptoms,” the researchers noted.
Now, the team, from Tianjin Medical University General Hospital in China, sought to understand the real-world relationship between MG and COVID-19, including how MG symptoms and infection may worsen each other. To that end, they conducted a retrospective study of 287 patients from this region in northern China.
The researchers also were interested in the effect of COVID-19 on the severity of MG symptoms and how immunosuppressive MG treatments affected COVID-19 susceptibility and severity.
Of all the MG patients included in this study, 243 were infected with COVID-19 during the Omicron variant wave. This variant quickly became the dominant strain of the virus due to its high transmissibility.
Of these COVID-19-infected patients, 229 had non-severe infections while 14 had severe or critical infections.
While the researchers did not find that clinical and demographic characteristics of MG increased the likelihood of a COVID-19 infection, they did find an association between multiple aspects of MG and the severity of patients’ COVID-19 infections.
Individuals who were older or had chronic comorbidities, or concurrent health conditions — which included asthma, chronic obstructive pulmonary disease, or pulmonary fibrosis — were more likely to have a severe infection of COVID-19.
Those with more severe MG symptoms before COVID-19 infection also were at greater risk of a severe or critical infection.
Given these findings, the researchers noted that “patients with inadequate control of MG symptom may need closer monitoring during the course of COVID-19 infection.”
MG treatments linked to different risks of MG exacerbations
Approximately one-third of the infected MG patients experienced MG exacerbations during COVID-19 infection. This included all 14 patients with severe or critical COVID-19 infections and about 30% of the MG patients with non-severe COVID-19 infection courses.
These MG exacerbations most commonly impacted eye-related or ocular muscles, with 45 of the 82 patients experiencing additional or worsening symptoms in those muscles. In contrast, 16 patients had additional or worse weakness in their respiratory muscles.
Of the patients with worsened MG, 32.9% received intravenous immunoglobulin to treat their symptoms. Seven patients required either noninvasive or invasive ventilation support or a combination of the two treatments.
MG exacerbations were more likely in older MG patients with chronic comorbidities. Having a history of more severe MG symptoms and more severe symptoms before COVID-19 infection were also associated with a higher likelihood of myasthenic exacerbations.
Severe to critical COVID-19 infection and having gMG symptoms were significant independent risk factors for MG exacerbation after COVID-19.
Patients with severe to critical COVID-19 infection also experienced earlier MG exacerbation after COVID-19 infection, with a median time to exacerbation of seven days from infection with severe infection, relative to a median time of 20 days for MG patients with non-severe infections.
We do not advocate an immediate cessation of ongoing immunosuppressive treatments once a COVID-19 infection is diagnosed. Instead, a judicious evaluation of the risks and benefits, tailored to each individual, is recommended.
MG treatments also were associated with different risks of MG exacerbations. Neither low (less than or equal to 20 mg) nor high (greater than 20 mg) dosing regimens of steroids were associated with exacerbations.
Treatment with nonspecific nonsteroidal immunosuppressants (tacrolimus, azathioprine, CellCept, and cyclophosphamide) or antibody therapies (IL-6 inhibitors, B-cell-depleting therapies, neonatal FC receptor inhibitors) was associated with a decreased risk of MG exacerbation after COVID-19 infection.
Given that immunotherapy treatment for MG did not lead to a more severe or critical infection course, and indeed reduced the risk of MG exacerbation, the researchers did not advocate for stopping immunosuppressive therapies in MG patients once a COVID-19 infection is diagnosed.
“We do not advocate an immediate cessation of ongoing immunosuppressive treatments once a COVID-19 infection is diagnosed,” the team wrote. “Instead, a judicious evaluation of the risks and benefits, tailored to each individual, is recommended.”
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