Epidemiology, characteristics, treatments, and outcomes of adult-onset Still's disease in Afro-Caribbeans: Results from a population-based study in Martinique, French West Indies.

OBJECTIVES: To describe the epidemiology, characteristics, response to initial treatment, and outcomes of Adult-Onset Still's disease (AOSD) in the Afro-Caribbean population of Martinique with free and easy access to specialised care.

METHODS: We conducted a retrospective study from 2004 to 2022 in the island of Martinique, French West-Indies which total population was 354 800 in 2021. Patients were identified from multiple sources including standardised databases. To be included, patients had to be residents of the island and fulfilled Yamaguchi and/or Fautrel's criteria for AOSD, or have a compatible disease course, without a diagnosis of cancer, auto-immune disease or another auto-inflammatory disorder. Date of diagnosis, clinical and biological characteristics, treatments, and outcomes were collected.

RESULTS: The prevalence was 7.6/100 000 inhabitants in 2021. The mean incidence was 0.4/100 000 during study period. Thirty-three patients (70.6% females) with a median follow-up of 35 months [7.5 to 119] were included. Twenty-six patients (78.8%) had a systemic pattern. Patients with a systemic monocyclic pattern had significantly more polyarticular involvement than patients with systemic polycyclic pattern (p = 0.016). Pulmonary involvement occurred in 51.5% of patients at diagnosis and systemic Pouchot score has been identified as an independent predictive factor for pulmonary involvement; OR of 3.29 [CI 95% 1.20; 9.01]. At first flare, all patients but one received oral glucocorticoids, 11 patients (32.4%) received intravenous glucocorticoids pulse and 12 patients (33%) received anti-IL1 therapy. Nineteen patients (57%) relapsed in a median time of 9 months [6 to 12] Three patients (9%) developed hemophagocytosis lymphohistiocytosis, fatal in 1 case. All deceased patients (n = 4, 11.76%) belonged to the systemic polycyclic pattern, with an event-free survival of 13.6 months [IQR 5.7; 29.5] CONCLUSION: AOSD in the Afro-Caribbean population of Martinique shares some similarities with other ethnic groups, but exhibit differences, such as a high proportion of lung involvement. Comparative studies are needed to confirm these results.