AB0694 Giant cell arteritis epidemiology in la reunion: a retrospective cases series
Authors: Q. Richier, T. Deltombe, A. Foucher, C. Roussin, A. Randrianjohany, A. Gerber, P. Poubeau, L. Raffray
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Giant Cell Arteritis (GCA) is the most common vasculitis in people over 50 years, with incidence varying according to geographic location. In Europe, the average incidence is 10–30 per 1 00 000 inhabitants over 50 years, whereas in Africa and Asia it is approximately 1.5 per 1 00 000. <h3>Objectives</h3> To define GCA epidemiology in La Réunion, a French oversea territory in South West Indian Ocean characterised by several ethnic groups and genetic admixture. <h3>Methods</h3> Retrospective study between January 2005 and August 2017 in the 4 main hospitals of La Réunion. Patients were identified through hospital informatics databases and practitioner records. A definite diagnosis of GCA was considered for patients fulfilling ACR criteria and/or by assessment by a trained rheumatologist. Incidence and prevalence calculation was based on French national census data. <h3>Results</h3> Sixty patients were included, of which 60% were women. Mean age at diagnosis was 73.7 years, with a mean delay to diagnosis of 6.8 months. Cases met an average of 3.78/5 ACR criteria, and 78% had &gt;2 criteria. The mean annual incidence was 2.33 per 1 00 000 inhabitants older than 50 years (203,000), with 95% confidency interval (IC) of 1.74–2.92. The prevalence at the end of period study was 24 cases per 100,00 (IC: 18–30). There was no seasonal variation regarding disease onset. Clinically, patients complained of asthenia and headache in 75%, fever in 33% and ophthalmologic damage for 32% of the cases, of which 5 had anterior ischaemic optic neuropathy. Polymyalgia rheumatica was associated in 42% of all cases. Total blood cells counts were usually within normal values, whereas mean CRP was 111 mg/L. Anicteric cholestasis was a common finding: mean GGT=78 IU/L (n&lt;42) and alkaline phosphatase=107 IU/L (n&lt;104). Radiological examinations contributed to diagnosis in only 9/31 cases. Temporal artery biopsy was performed in 91% of patients and showed specific histological features of GCA in 55%. Corticosteroid regimen was introduced in 59 patients (1 died the day after the biopsy) and mean treatment duration was 26 months, for a total dose of 10.6 g. Antiplatelet therapy was given in 47% of patients. One patient in three experienced one or more relapses. <h3>Conclusions</h3> This is the first study to describe GCA in La Réunion, and more generally in Indian Ocean. It shows an incidence 4–12 times lower than in most European countries with white ancestry background. This discrepancy could be explained by the contribution of the various ethnic groups of La Reunion, especially those coming from parts of the world characterised by a lower GCA incidence (Africa, India, South East Asia). A shorter life expectancy may also account for this observation, assuming that GCA incidence increases with age. Sex ratio and age at diagnosis were similar to European studies, as well as clinico-biological features, response to treatment and side effects. Some limitations of our study should be taken in consideration: inclusions of hospitalised patients only, informatics record limits and retrospective design that did not afford for ethnic background determination. <h3>Reference</h3> [1] Mahr A, et al. [Epidemiology and natural history of giant cell arteritis]. Rev Med Interne. 2017Oct;38(10):663–669. <h3>Disclosure of Interest</h3> None declared