Ethnic Differences in Juvenile Idiopathic Arthritis in the Circumpolar Region

Rheumatic diseases, including spondyloarthritis, systemic lupus erythematosus, Takayasu's nonspecific aortoarteritis, Behcet's disease, and Kawasaki disease, are more prevalent among Asian populations. The indigenous Sakha people, who live in the harsh conditions of the North and the Arctic regions, exhibit a unique pattern of health issues.

The objective of the study is to characterize the ethnic characteristics of juvenile idiopathic arthritis (JIA) among children from the indigenous population of the Republic of Sakha (Yakutia) and compare them with Caucasians (Russians) living in the same region. This comparison aims to inform the development of tailored diagnostic and treatment strategies.

The comprehensive, single-center, retrospective cohort study included medical data of all Sakha (n = 168) and Russian ethnic patients (n = 48) with JIA who were examined and treated at the Pediatric Center's Cardiorheumatology Department at the Republican Hospital No. 1-M.E. Nikolaev National Center of Medicine-between 2016 and 2023. The ethnicity was self-reported. The standard clinical procedures and laboratory assessments, as well as the current treatment regimen, were thoroughly reviewed.

It was found that children of Sakha descent had a later onset of juvenile idiopathic arthritis (JIA), which was associated with the enthesitis-related arthritis (ERA) categories (51.2% vs. 18.3%, p = 0.0002). They also exhibited higher prevalence of enthesitis (19% vs. 2.0%, p = 0.003), sacroiliitis (23.8% vs. 2.0%, p = 0.0003), and HLA-B27 antigen positivity (46.3% vs. 14.6%, p = 0.00005). The Sakha population exhibited a notably higher prevalence (41.7%) of ERA, compared to the Russian population (33.3%; p = 0.0003), and they initiated biologic therapy at a later stage. However, remission rates were lower among Sakha children (29.2%) than among Russian children (72.2%, p = 0.002), as was their likelihood of achieving remission (Log-Rank test, p = 0.005), regardless of the JIA categories (p = 0.008). Sakha children had a 64.4% reduced chance of achieving remission on the first bDMARD, compared to Russian children (HR = 0.36, 95% CI: 0.18-0.71, p = 0.004).

Distinct variations in the progression and treatment outcomes of JIA were observed between Sakha children and Caucasians. A tailored approach to the care of JIA patients is essential, considering their ethnic background.