Clinical characteristics and associated factors of cardiovascular involvement in patients with relapsing polychondritis

Aims To analyze the clinical characteristics and identify factors associated with cardiovascular involvement in patients with relapsing polychondritis (RP). Methods A total of 105 RP patients were enrolled and divided into cardiac and non-cardiac groups. Demographic, clinical, and serological data were collected and analyzed comparatively. Univariate and Firth's logistic regression analyses were performed to identify independent factors associated with cardiac involvement. Hierarchical clustering was applied to explore phenotypic patterns. Results Among the RP cohort, 29.5% (31/105) exhibited cardiovascular involvement, with a male-to-female ratio of 16:15 and a mean age of 57.87 ± 12.06 years. Manifestations included aortic root dilatation (11.4%), conduction abnormalities (8.6%), myocarditis (7.6%), pericarditis (5.7%), and valvular dysfunction (3.8%). Patients with cardiac involvement exhibited a significantly lower prevalence of ocular involvement (12.9 vs. 36.5%; P = 0.016) and a non-significant trend toward lower frequency of costochondritis (9.7 vs. 24.3%; P = 0.087). Notably, low-density lipoprotein (LDL) levels were significantly lower in the cardiac involvement group [2.60(1.00, 4.37) vs. 2.84(1.45, 5.30) mmol/L; P = 0.041]. Firth's logistic regression identified the ocular involvement (OR: 0.22, 95% CI: 0.06–0.78; P = 0.010), costochondritis (OR: 0.26, 95% CI: 0.07–0.99; P = 0.029), and LDL levels (OR: 0.51, 95% CI: 0.27–0.93; P = 0.017) as independent factors associated with cardiac involvement. Clustering analysis identified five phenotypic groups, with the “tracheobronchi-cardiac” cluster showing the lowest LDL levels and the smallest proportions of ocular and costal cartilage involvement. Conclusions Cardiac involvement in RP is not rare and is independently associated with lower LDL levels and reduced frequencies of ocular and costal cartilage involvement. These findings may help identify RP patients at risk for cardiac manifestations and suggest potential protective roles of certain clinical features.