Giant cell arteritis in Black Caribbean patients: incidence, clinical features and outcomes of a 31-year population-based study of biopsy-proven cases in Martinique

Abstract Background Giant Cell Arteritis (GCA) is poorly known in Black patients. Our objective was to describe the incidence and characteristics of GCA in the Black Caribbean population of Martinique. Methods In this population-based retrospective observational study, all cases with a positive temporal artery biopsy diagnosed between 1991 and 2022 were collected from the two pathology laboratories of the island of Martinique (one public, one private). Population denominators were obtained from the yearly estimates of the French National Institute for Statistics (INSEE), and incidence rates were expressed per 100,000 inhabitants in the population aged 50 years and above. Poisson regression models were fitted to estimate risk ratios by sex, and age group. GCA incidence and patient characteristics were analysed and compared to published series. Results 43 biopsy-proven GCA were reported in Black patients over the age of 50. Mean annual GCA incidence rate was 1.761/100,000 person-years in the population aged 50 years and above. The incidence rate rose from 0.777 (0.774–0.781) between 1991 and 1995 to 3.132/100,000 (3.127–3.136) between 2011 and 2016. Age at diagnosis was 76.3 ± 7.6 years, with a female: male ratio of 4.4. Initial manifestations were mainly: headache (65.1%), jaw claudication (32.6%), scalp tenderness (37.2%), anterior ischemic optic neuropathy (25.6%) and polymyalgia rheumatica (32.6%). Mean survival time was 13 ± 2 years, with an average relapse-free period of 6 ± 1 year. Conclusions This population-based study of Black patients found a lower incidence of GCA in patients compared to White/Caucasian patients. However, the incidence is increasing and GCA is likely to be diagnosed more frequently in this population in the coming years. Trial registration N/A.