Disease patterns of patients with Behcet's disease demonstrated by factor analysis

Objective: To explore the main patterns of Behcet's disease (BD) expression, applying factor analysis. Methods: Sixty-eight BD patients were studied. The following disease manifestations were used for the factor analysis: genital ulcerations, typical skin lesions (erythema nodosum, folliculitis or papulo-pustular rash), uveitis, CNS involvement, joint disease, deep vein and superficial vein thrombosis, and gastrointestinal manifestations. The results were further analyzed according to sex, HLA typing, and childhood vs. adult-onset disease. Results: Five factors were derived, which accounted for 69% of the variance of the matrix. Factor 1 represented the association between folliculitis and genital ulceration. Factor 2 represented the association between papulo-pustular rash and gastrointestinal symptoms. Factor 3 represented the inverse association between superficial vein thrombosis and erythema nodosum. Factor 4 represented the correlation between deep vein thrombosis and neuro-Behcet. Factor 5 represented joint disease. No difference was found between males and females in relation to factors 1, 2 or 5, but factors 3 and 4 had higher scores in male patients (p = 0.1 and p = 0.07, respectively). Factor 3 was significantly higher in patients with HLA-B5, compared to HLA-B5-negative BD patients (p < 0.001). Factors 1 and 3 were higher in patients with adult onset of the disease (p = 0.07, and p = 0.003, respectively), while factor 2 was higher in patients with childhood-onset BD (p = 0.07). Conclusions: The application of factor analysis revealed possible associations between distinct types of skin lesions, or venous thrombosis, and other disease manifestations of Behcet's syndrome, some of which were sex, age at onset, or HLA-related.