1180: Gender-Based Clinical Differences in Behçet’s Syndrome: Findings from a 24-Year Cohort in a Non-Endemic and Multiethnic Country

Background/Purpose: Behçet’s syndrome (BS) is a multisystemic inflammatory condition that affects both genders, although gender-related differences in disease manifestations may vary across regions. Studies report severe manifestations more commonly in men. However, gender-based differences in South America, a non-endemic region, have been less studied.

Methods: This is a retrospective analysis of a prospective, single-center, multiethnic cohort of patients with BS from January 2000 to December 2024. Patients were diagnosed according to the International Study Group and/or the International Criteria for Behçet's Syndrome. Categorical variables were analyzed using the chi-square test or Fisher’s exact test, while continuous variables were compared using unpaired Student’s t-test.

Results: Among 369 patients evaluated, 303 were included, of whom 117(38.6%) were male and 186(61.4%) were female. The mean age at symptom onset was 27.4±11.4 years, with males presenting at 25.9±10.4 years and females at 28.3±12.0 years (p=0.075). The mean age at diagnosis was 31.6±10.4 years, with no significant difference between sexes (p=0.082). The most prevalent clinical manifestations were oral ulcers (99.3%), genital ulcers (81.5%), pseudofolliculitis (51.5%) and erythema nodosum-like lesions (35%). Female patients more frequently presented genital ulcers (89.2% vs. 69.2%; p< 0.001), erythema nodosum-like lesions (39.2% vs. 28.2%; p=0.050) and arthritis (38.2% vs. 26.5%; p=0.036). Conversely, male patients more often exhibited acne (19.7% vs. 5.9%; p< 0.001), deep vein thrombosis of the limbs (26.5% vs. 12.9%; p=0.003), caval vein thrombosis (7.7% vs. 2.2%; p=0.020), peripheral artery aneurysms (8.5% vs. 2.2%; p=0.010), arterial occlusions (11.1% vs. 4.3%; p=0.023), posterior uveitis/retinal vasculitis (24.8% vs. 15.1%; p=0.035) and panuveitis (10.3% vs. 2.7%; p=0.005). Azathioprine use was more common among males (75.2% vs. 64%; p=0.041). Fibromyalgia was significantly more prevalent in female patients (18.3% vs. 1.7%; p< 0.001). No gender differences were observed regarding the use of other medications or comorbidities.

Conclusion: This is the largest cohort in South America to evaluate gender-specific features in BS. Male patients were more likely to exhibit severe manifestations, consistent with existing literature. Female patients showed a higher prevalence of mucocutaneous lesions, arthritis, and fibromyalgia. Although these manifestations are often considered benign, they can significantly affect quality of life. The higher prevalence of fibromyalgia in women may reflect the general higher incidence of this condition in females, but arthritis may also trigger central nervous system sensitization, making women more susceptible. This hypothesis requires further investigation. The higher use of azathioprine in male patients suggests the need for more aggressive immunosuppression due to the severity of their symptoms. This difference may also reflect a more conservative treatment approach for women, given the perceived milder nature of their manifestations.