Sex-Related Differences in Clinical Phenotypes and Outcomes in Adult Onset Still’s Disease

Objective: Biological sex may affect the disease course and prognosis of several inflammatory diseases. This study aimed to analyze the influence of gender on the clinical profile, complications, and therapeutic response in patients with Still's Disease (SD). Methods: We conducted a multicenter, prospective, observational, nationwide study to include patients with Adult Onset Still’s Disease (AOSD). The different clinical manifestations, biological features, disease course, complications, and therapeutic responses were compared between male and female patients. Results: A total of 80 patients were included. Comparative analysis showed a female predominance with sex ratio male to female at 0.6 (31 (38.7%), 49 (61.2%), p=0.04), while AOSD males were younger than females (30.58 ± 11.74, 35.77 ± 13.57, p=0.08). Urticarial rash (p < 0.0001) with dermographism (p= 0.02) and lymphadenopathy (p=0.007) were significantly associated with females, while typical rash (p=0.01) and hepatitis (p=0.004) were significantly more frequent in males. Moreover, myocarditis (4/5) was more frequent in males, whereas macrophage activation syndrome (5/6) was more frequent in females. No significant differences were noted between males and females in the disease course (p=0.4), therapeutic response, and occurrence of erosive arthritis (p= 0.8). Conclusion: women exhibited a higher prevalence and distinct clinical features compared to men, suggesting sex- specific phenotypes. There were no differences between males and females in the disease course, therapeutic response, and occurrence of erosive arthritis despite phenotypic differences.