Risk of Infection in Patients with Myasthenia Gravis With and Without Thymoma (P2-8.008)

Abstract

<h3>Objective:</h3> To assess the risk of infection in patients with myasthenia gravis (MG) with thymoma compared to MG patients without thymoma. <h3>Background:</h3> MG is treated with multiple immunosuppressive agents and is sometimes associated with thymoma, which may increase the risk of infection further. Understanding infection risk may help with degree of immunosuppression and attempts to prevent infection with prophylactic vaccination/antibiotic treatments. <h3>Design/Methods:</h3> Retrospective analysis of all adult patients with AChR+ve MG at our center from 2015 to 2022 was performed. Rates of herpes zoster, pneumonia, UTI, meningitis, pneumocystis jirovecii pneumonia, sepsis, CMV infections, and morbidity were analyzed in MG patients with or without a history of thymoma. We used descriptive statistics and propensity score (PS) matching for comparative analysis. Infections within 6 months of chemotherapy were excluded. <h3>Results:</h3> We identified 141 patients diagnosed with AChR+ve MG, 30 with thymoma, and 111 without thymoma. The thymoma group had a higher percentage of females and patients of Asian descent, but similar ages. Comorbidity scores were similar, but the thymoma group had higher rates of chronic pulmonary disease. Baseline measures were notable for more neurologic diagnoses and higher immunosuppressant use in the thymoma group. The unadjusted rates of all infections during the follow up period were 37% in the thymoma group and 11.7% in the non-thymoma group; this was significant in the unmatched and basic-matched analyses (OR 16.1, 95% CI: 2.04 to 744, p = 0.002) but not after PS-matched analysis (OR 1.75, 95% CI: 0.52–5.87, p=0.36). Rates of pneumonia and sepsis were significantly higher in the thymoma group in unmatched, but not in the PS-matched, analysis. Rates of CMV, Zoster, UTI, and death were similar. <h3>Conclusions:</h3> The rates of all non-chemotherapy related infections in patients with MG and thymoma are higher compared to MG patients without thymoma but are similar after adjusting for comorbidities and observable confounders. <b>Disclosure:</b> Dr. Clifford has nothing to disclose. Dr. McKeen has nothing to disclose. Dr. Yuan has received personal compensation for serving as an employee of Atropos Health. Dr. Muppidi has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alexion. Dr. Muppidi has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for argenx. Dr. Muppidi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB/Ra Pharma. Dr. Muppidi has received publishing royalties from a publication relating to health care.