Lifetime clinical presentation of Still's disease in the Afro-descendant population of the French West Indies

Introduction: The continuum in Still's disease has never been addressed in Afro-descendant (AD) populations. The aim of this study was to compare the features of Still's disease between children and adults in the AD population of French West Indies (FWI).

Methods: Retrospective longitudinal study from January 2000-2022. We included children and adults with systemic juvenile idiopathic arthritis and Still's disease. Clinical data were obtained from computerized hospital archives, registries of clinicians and the national registry for rare diseases. The main outcome was similarity in cardinal and non-cardinal symptoms.

Results: Fifty-eight patients were included (57% adults). Sex distribution between children and adults was significantly different (Female respectively 36% vs 70.6%, P=0.03). Diagnostic criteria overlapped in most cases (80%), regardless of age. The children had significantly more typical skin rashes (100% vs 29.4%, P<0.001), coronary artery dilation (16% vs 0%, P=0.03), and macrophage activation syndrome (52% vs 9%, P<0.001). The adults had significantly more inflammatory polyarthalgia without arthritis (91% vs 32% P<0.001) and pulmonary involvement (51.5% vs 4% P<0.001). The phenotypes were 86% systemic (43% monophasic, 43% polycyclic) and 14% chronic polyarticular. No difference was found in the number of relapses, use of biologics and mortality.

Conclusions: There is a rationale for considering Still's disease as a single entity in our AD population, focusing on the cardinal symptoms, but particular attention should be paid to the non-cardinal symptoms depending on the age of onset.