Cluster and correspondence analyses for oral ulcer activity related factors in Behçet's syndrome

Behçet's Syndrome (BS) is a multisystemic vasculitis characterized by a heterogeneous clinical profile, including mucocutaneous, musculoskeletal, neurological, ocular, vascular and gastrointestinal manifestations. BS patients often experience a continuous, low-level disease activity state due to persistent oral ulcers. This study aimed to define relations among oral ulcer activity (OUA), gender and treatments through K-Means Cluster and Correspondence Analyses (CA) in patients with BS.

In this cross-sectional study, 526 BS patients from two tertiary centres in Turkey and the United Kingdom were included. The K-Means Cluster Analysis was performed to identify homogeneous clinical profiles for OUA by combining the disease severity score reflecting organ involvement and the number of oral ulcers. Then, CA was performed to visualize associations between gender and medications (non-immunosuppressive: non-IS vs. IS) in clusters.

K-Means Analysis identified three clusters regarding mucocutaneous and major organ involvement and cluster regarding with major organ involvement. Clusters were named according to OUA and the disease severity. The number of oral ulcers was found to be similar in the "Low OUA" cluster (n=202, 65.03%; 2.18±1.13) and the "Low OUA with Major Organ Involvement" cluster (n=63, 19.25%; 2.19±1.37) (p=0.368). These were lower than those in the "Moderate OUA" Cluster (n=30, 9.8%; 7.60±1.88) and the "High OUA" cluster (n=11, 3.59%; 14.91±2.34) (p<0.001). CA visualized that non-ISs in "Low OUA" cluster, ISs in "Low OUA with Major Organ" cluster for both genders as well as male patients treated with non-ISs or ISs in "Moderate OUA" cluster were predominant groups.

The presence of two oral ulcers might be accepted as the cut-off value for low OUA. Moreover, intensive treatment protocols must be provided for elevated oral ulcer activity in male patients who were treated with non-IS medications in BS.