Geographical variations in ocular and extra-ocular manifestations in Behçet's disease.

Objective: Behçet's disease (BD) is a rare vasculitis that results in multi-organ inflammatory disease. At-risk populations are most prevalent in the Middle East and East Asia. Clinical data on BD in Western countries, especially in the United States, are scarce. We have compared clinical patterning of BD vasculitis in two geographically defined patient cohorts in the Western United States and Iran.

Methods: Comparative analysis of a retrospective cohort of 56 patients with BD evaluated at Stanford University Hospital between 2000 and 2016 and a cohort of 163 patients from the BD Registry at Tehran University of Medical Sciences. Clinical, demographic, laboratory, and treatment data were available. Comparisons were performed using descriptive statistics, Student's t-test, and χ-test.

Results: The Stanford patients with BD were significantly younger at disease onset, had a higher proportion of females, and had longer disease duration than Iranian patients with BD. Genital ulcers, skin, joint, neurological, vascular, cardiopulmonary manifestations were all significantly more common in the Stanford cohort and 38% of Stanford patients had four or more organ systems involved compared with approximately 10% of Iranian patients. In contrast, Stanford patients had fewer ocular lesions (Stanford 21.4% vs. Iran 53.4% p<0.05), with the biggest difference seen for retinal vasculitis.

Conclusion: Patients with BD from the Western US have a more severe disease course when compared to Iranian patients with BD, as demonstrated by earlier onset and a higher rate of multi-organ involvement. The high risk of Iranian patients with BD developing vasculitis of ocular structures suggests distinct pathomechanisms driving ocular versus extra-ocular BD.