COVID-19 infection in myasthenia gravis: Clinical course and outcomes

Clinical features of COVID-19 infection in patients with myasthenia gravis: a real-world retrospective study

Objective

We investigated the risk factors associated with severe or critical Coronavirus disease 2019 (COVID-19) infection due to the Omicron variant in patients with myasthenia gravis (MG) and determined the potential effect of COVID-19 on myasthenic exacerbation during the Omicron pandemic.

Methods

This retrospective study included 287 patients with MG in Tianjin, China. Clinical data of the patients were collected using electronic questionnaires, databases, and clinical records.

Results

The overall infection rate was 84.7%. Advanced age, comorbidities, generalized phenotype, and MG instability were drivers of COVID-19 severity, and post-COVID-19 myasthenic exacerbation. The concurrent use of a steroid-sparing agent did not affect COVID-19 susceptibility or severity. It did lower the risk of myasthenic exacerbation after COVID-19 infection. Patients with severe COVID-19 experienced myasthenic exacerbation earlier than patients with non-severe infection (p < 0.001). The severity of COVID-19 (Hazards Ratio = 3.04, 95% CI: 1.41-6.54, p = 0.004) and the clinical phenotype (Hazards Ratio = 3.29, 95% CI: 1.63-6.63, p < 0.001) emerged as independent risk factors for early MG exacerbation.

Conclusion

Generally, patients with MG appear to be susceptible to the Omicron strains. Immunotherapy for MG did not increase COVID-19 susceptibility or severity. 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.

Impact of COVID-19 Infection and Its Association With Previous Vaccination in Patients With Myasthenia Gravis in Korea: A Multicenter Retrospective Study

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, patients with myasthenia gravis (MG) were more susceptible to poor outcomes owing to respiratory muscle weakness and immunotherapy. Several studies conducted in the early stages of the COVID-19 pandemic reported higher mortality in patients with MG compared to the general population. This study aimed to investigate the clinical course and prognosis of COVID-19 in patients with MG and to compare these parameters between vaccinated and unvaccinated patients in South Korea.

METHODS

This multicenter, retrospective study, which was conducted at 14 tertiary hospitals in South Korea, reviewed the medical records and identified MG patients who contracted COVID-19 between February 2022 and April 2022. The demographic and clinical characteristics associated with MG and vaccination status were collected. The clinical outcomes of COVID-19 infection and MG were investigated and compared between the vaccinated and unvaccinated patients.

RESULTS

Ninety-two patients with MG contracted COVID-19 during the study. Nine (9.8%) patients required hospitalization, 4 (4.3%) of whom were admitted to the intensive care unit. Seventy-five of 92 patients were vaccinated before contracting COVID-19 infection, and 17 were not. During the COVID-19 infection, 6 of 17 (35.3%) unvaccinated patients were hospitalized, whereas 3 of 75 (4.0%) vaccinated patients were hospitalized (P < 0.001). The frequencies of ICU admission and mechanical ventilation were significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.019 and P = 0.032, respectively). The rate of MG deterioration was significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.041). Logistic regression after weighting revealed that the risk of hospitalization and MG deterioration after COVID-19 infection was significantly lower in the vaccinated patients than in the unvaccinated patients.

CONCLUSION

This study suggests that the clinical course and prognosis of patients with MG who contracted COVID-19 during the dominance of the omicron variant of COVID-19 may be milder than those at the early phase of the COVID-19 pandemic when vaccination was unavailable. Vaccination may reduce the morbidity of COVID-19 in patients with MG and effectively prevent MG deterioration induced by COVID-19 infection.

[Eculizumab led to beneficial clinical course in a patient with generalized myasthenia gravis who developed COVID 19-associated pneumonia]

A 74-year-old woman developed myasthenia gravis (MG) at the age of 32. She had a thymoma removed the following year, but her MG symptoms did not stabilize, and she required frequent hospitalization for fast-acting treatment (FT). She started eculizumab in March of two years ago and was followed up on an outpatient basis as her MG symptoms became milder. In February of this year, she was admitted to our hospital due to mild COVID-19-associated pneumonia with general malaise and fever. Her COVID-19-associated pneumonia was treated with intravenous sotrovimab, dexamethasone, and unfractionated heparin, and oral therapy for MG stayed the same. Eculizumab was not administered during hospitalization due to the combination of stable MG symptoms and the fact that the drug is not paid for by the Japanese insurance system. The patient's MG and COVID-19-associated pneumonia were not severe during hospitalization. However, the risk of myasthenic crisis and death is high when patients with MG develop COVID-19-associated pneumonia. Several reports suggest that the condition of patients with eculizumab-treated MG who develop COVID-19-associated pneumonia is not severe, and that that inhibition of the complement pathway with eculizumab is effective for COVID-19-associated pneumonia. Complement deposition in organ microvessels has been observed in patients with COVID-19, which suggests that complement overload may be a risk factor for COVID-19-associated pneumonia. Excessive complement activation may be involved in the pathogenesis; thus, eculizumab may function by inhibiting this pathway. In this case, eculizumab was discontinued while the patient had COVID-19-associated pneumonia, however, CH50, which is an indicator of complement, was suppressed during hospitalization due to the COVID-19-associated pneumonia. Therefore, eculizumab may have interfered with this course of events. This case demonstrates that eculizumab may be safe for and tolerated by patients with MG and COVID-19-associated pneumonia, but more cases need to be accumulated to support this conclusion.

Association between COVID-19 and myasthenia gravis (MG): A genetic correlation and Mendelian randomization study

BACKGROUND

Observational studies have suggested an association between coronavirus disease 2019 (COVID-19) and myasthenia gravis (MG). Here, we aimed to estimate the genetic correlation and causal relationship between COVID-19 susceptibility, hospitalization, severity, and MG phenotypes using linkage disequilibrium score regression (LDSC) and Mendelian randomization (MR) approach.

METHODS

Summary statistics of COVID-19 susceptibility, hospitalization, and severity were used as instrumental variables for exposure traits. Large-scale genome-wide association study (GWAS) data for MG were used as outcome traits. The inverse variance weighted approach was used for the main MR analysis, complemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Sensitivity analysis was implemented using Cochran's Q test, MR-PRESSO method, and MR-Egger intercept test.

RESULTS

LDSC analysis did not reveal any genetic correlation among COVID-19 susceptibility, hospitalization, severity, and MG phenotypes, including MG, early-onset MG, and late-onset MG (p > .05). Our MR analysis did not provide evidence supporting a causal effect of COVID-19 susceptibility, hospitalization, or severity on MG phenotypes (p > .05). Extensive sensitivity analysis strengthened the robustness and consistency of the MR estimates.

CONCLUSION

Our study did not find evidence of a genetic correlation or causal relationship among COVID-19 susceptibility, hospitalization, severity, and MG. Future studies with more GWAS data are needed to evaluate the association between COVID-19 phenotypes and MG and its subgroups.