Bronchiectasis in Myasthenia Gravis: A Clinically Relevant Comorbidity Defining a High-Risk Triad with Thymoma 2307376

Abstract Introduction Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction, leads to fluctuating muscle weakness, may involve respiratory muscles, and may progress to myasthenic crisis. Bronchiectasis (BE), a chronic airway disease with a prevalence of 234/100,000 in Israel, is described in association with thymic tumors. Its prevalence and clinical relevance in MG remain undefined. Methods We retrospectively studied 238 patients with MG. Demographic, clinical, and immunological data were collected, and BE was confirmed by high-resolution chest CT. A comparison group of 111 patients with thymoma but without MG was evaluated for BE prevalence. Group comparisons were performed using Fisher’s exact test. Logistic regression was used to assess the independent and combined effects of MG and thymoma on BE risk, including interaction analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to quantify associations. Results BE was more frequent in patients with both MG and thymoma (19.6%) compared to MG without thymoma (5.9%, OR 3.9, 95% CI 1.6—9.8, p = 0.0047), thymoma without MG (3.6%, OR 6.5, 95% CI 1.9—22, p = 0.0016), and the general population (0.23%). ORs for BE were significantly elevated in all subgroups compared to the general population: 104.0 (95% CI 51.5—210.0, p = 7.2 × 10⁻17), 26.6 (95% CI 14.3—49.7, p = 1.9 × 10⁻¹²), and 15.9 (95% CI 5.8—43.6, p = 1.5 × 10-4), respectively. MG and thymoma were independently associated with BE, but a negative interaction term (β = —1.41, p = 0.043) suggested overlapping mechanisms. BE was associated with increased risk of myasthenic crisis (30.4% vs. 6.7%, OR = 6.1, p = 0.0017), especially in the presence of thymoma (60% vs. 8.3%, OR = 16.5, p = 0.020). Conclusion Bronchiectasis is an underrecognized but clinically relevant comorbidity in MG, particularly with thymoma, forming a triad associated with a high-risk disease phenotype. Its presence may reflect an autoimmune-mediated form of BE linked to the MG-thymoma spectrum. Funding Source There is no funding for this project Topic Categories Immune Mechanisms of Human Disease (HUM)