Phenotypic clusters of patients with Takayasu arteritis predict disease activity at presentation, damage and future vascular complications

Objective To identify clusters of Takayasu arteritis (TAK) based on clinical features and their prognostic relevance. Methods Using agglomerative hierarchical clustering, clusters were defined on phenotype at presentation from 564 patients with TAK from three cohorts from India and Türkiye. Angiographic involvement, disease activity and Vasculitis Damage Index (VDI) at presentation, initiation of glucocorticoids or immunosuppressive agents, requirement for vascular procedures, and new-onset vascular complications were compared between clusters [unpaired Student’s t test or odds ratios (OR with 95%CI)]. Mortality rates [hazard ratios (HR) with 95%CI] were computed using Cox regression. Results Three clusters were identified (1 and 2, with sub-clusters 2A and 2B). Cluster 2 was younger and comprised relatively fewer women than cluster 1. Clinical features and angiography in cluster 1 reflected more frequent involvement of the arch of aorta and its branches as opposed to a greater involvement of the abdominal aorta and its branches in cluster 2. Cluster 2B more often had pan-aortic disease and left subclavian involvement than 2A. Fewer patients in cluster 2A were initiated on glucocorticoids [OR adjusted for center (aOR) 0.51 (0.31-0.83)] or immunosuppressants [aOR 0.35 (0.20-0.60)] or developed new-onset vascular complications [aOR 0.22 (0.07-0.74)] than cluster 1. Cluster 2B had higher VDI (3.98) than clusters 1(3.50) or 2A (2.46) and required more frequent vascular interventions than Cluster 1 or 2A (aOR 1.73-1.88, p < 0.05). Survival was similar across clusters [HR 2A vs 1 0.99 (0.43-2.29), 2B vs 1 1.20 (0.84-1.70)]. Conclusion Phenotypic clusters of TAK reflected distinct angiographic involvement with prognostic implications.