Prevalence and incidence of systemic lupus erythematosus in Thailand based on national health data.

BACKGROUND

SLE is an autoimmune disease that varies across ethnic populations and the regions that cause economic burdens, but nationwide epidemiological data for Thailand are lacking.

OBJECTIVE

To estimate the incidence and prevalence of SLE in Thailand between 2017 and 2020.

METHODS

A retrospective cohort study used the Information and Communication Technology Center, Ministry of Public Health, covering all major healthcare insurance systems (nearly 90% of hospitals, about 80% of the Thai population). Adults (≥18 years) with a primary diagnosis of SLE (International Classification of Diseases 10th Revision code M32) were included. Point and period prevalence (per 100 000 population) and annual incidence rates (per 100 000 person-years) were calculated overall and stratified by year, age, sex and region, with 95% CIs.

RESULTS

In 2017, 55 956 prevalent cases were identified among 65 204 797 of the total Thai population, yielding a point prevalence of 85.8/100 000 (95 % CI 85.1 to 86.5). Prevalence was highest in women (152.9 vs 15.9/100 000; female-to-male ratio 9.6:1), in the 40-49 year age group (128.3/100 000) and in the southern region (178.5/100 000). From 2018 to 2020, incident SLE cases numbered 15 403, 16 243 and 15 925, corresponding to annual incidence rates of 23.6, 24.8 and 24.3/100 000 person-years, and the cumulative incidence for the 3 years was 72.7/100 000 person-years (95 % CI 72.0 to 73.4). Incidence peaked at ages 40-49 in 2019 (33.7/100 000) and was consistently highest in the south (60.0, 53.9 and 57.3/100 000 person-years in 2018-2020).

CONCLUSIONS

SLE is relatively common in Thailand, particularly among women of reproductive age and residents of the southern region. These nationwide data support SLE service planning in Thailand and may guide resource allocation in other Southeast Asian health systems expanding universal coverage.