Clinical phenotypes of adult-onset Behçet's syndrome: a comprehensive cross-sectional study in China.

Behçet's syndrome (BS) is a variant vasculitis that can involve multiple organs with inflammatory manifestations. This study aimed to provide a more comprehensive analysis of the clinical phenotypes and characteristics of BS patients. We enrolled 2792 BS patients referred from China nationwide to Huadong Hospital Affiliated to Fudan University from October 2012 to December 2022. Detailed assessments of demographic information, clinical manifestations, laboratory results, gastroscopy, and medical imaging were conducted. Cluster analysis was performed based on 13 variables to determine the clinical phenotypes, and each phenotype was characterized according to the features of BS patients. A total of 1834 BS patients were included, while 958 invalid patients were excluded. The median age at onset was 31 years (IQR, 24-40 years), and the median disease duration was 10 years (IQR, 5-15 years). Eight clusters were identified, including mucocutaneous (n =  655, 35.7%), gastrointestinal (n =  363, 19.8%), articular (n =  184, 10%), ocular (n =  223, 12.2%), cardiovascular (n =  119, 6.5%), neurological (n =  118, 6.4%), vascular (n =  114, 6.2%), and hematological phenotype (n =  58, 3.2%). Ocular (RR =  1.672 (95% CI, 1.327-2.106); P <  0.001), gastrointestinal (RR = = 1.194 (95% CI, 1.031-1.383); P =  0.018), cardiovascular (RR = = 2.582 (95% CI, 1.842-3.620); P <  0.001), and vascular (RR = = 2.288 (95% CI, 1.600-3.272); P <  0.001) involvement were more prevalent in male BS patients, while the hematological (RR =  0.528 (95% CI, 0.360-0.776); P =  0.001) involvement was more common among female patients. BS presents significant heterogeneity and gender differences. The eight phenotypes of BS patients we propose hold the potential to assist clinicians in devising more personalized treatment and follow-up strategies. Key Points • This cluster analysis divided adult-onset BS into eight clinical phenotypes. • BS demonstrates a high level of clinical heterogeneity and gender differences. • Hematologic phenotypes of BS present distinctive clinical characteristics.