Latent Class Analysis to Explore Subtypes of EGPA: Focusing on Respiratory Involvement and Inflammation Markers

Eosinophilic granulomatosis with polyangiitis (EGPA) was regarded as a heterogeneous disease with respiratory involvement manifested in various patterns. This study aimed to explore whether subtypes with different clinical features and outcomes could be identified by latent class analysis (LCA) from the perspective of the respiratory system in patients with EGPA.

Patients diagnosed with EGPA between January 2000 and December 2022 were included. The clinical data and survival of the individuals were collected. Subtypes were identified using LCA according to organ involvement and anti-neutrophil cytoplasmic antibody (ANCA) status in model 1, according to patterns of respiratory involvement, other organ involvement, ANCA status, and inflammatory markers in model 2. The characteristics and prognosis of the classes were compared.

Out of the 330 patients initially diagnosed with EGPA, 245 patients were included eventually. In model 1, 138 (56.3%) and 107 (43.7%) patients were identified in classes 1 and 2, respectively. Class 2 was older (P = .017), had less musculoskeletal, mucocutaneous, cardiovascular, gastrointestinal, and peripheral nervous involvement (all P < .001) compared to class 1. No significant difference in overall survival was found between the classes. In model 2, LCA assigned 165 (67.3%) participants to class 1 (systemic EGPA) and 80 (32.7%) to class 2 (respiratory-limited EGPA). Compared with class 1, class 2 was younger (P < .001) and had lower levels of inflammation markers (white blood cell, eosinophil, erythrocyte sedimentation rate, and C-reactive protein: P < .001). Besides, patients in class 2 were more likely to have airway involvement, including the onset of asthma (P = .041), FEV1/ FVC < 70% (P < .001), and bronchiectasis (P < .001). Moreover, class 2 exhibited better survival compared to class 1 (P = .001).

The respiratory-limited EGPA may be the relatively milder type of disease. Other organ functions, serum inflammatory markers, and ANCA should be monitored during follow-up in these patients. Cite this article as: Gu Y, Liu Y, Zhang T, Han Y, Peng M, Shi J. Latent class analysis to explore subtypes of EGPA: Focusing on respiratory involvement and inflammation markers. Arch Rheumatol. 2026;41(2):81-89.