Analysis of Socioeconomic Status in the Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory disease with different etiologies in different areas. Our study focused on the prevalence of RA in Taiwan from 2001 to 2011. This study contained longitudinal enrollment files, claims data, catastrophic illness files, and treatment registries from Taiwan Longitudinal Health Insurance Research Database. We identified RA patients by ICD-9-CM code 714.0. The demographical variables including age, sex, income and area of registration were evaluated. The multivariate Poisson regression was applied to calculate relative risk for developing RA. In Taiwan, the ratio of female to male was about 5:1. From 2001 to 2011, significant increasing prevalence of RA, from 0.07% to 0.14%, was found in women. The prevalence of RA was increasing 6% per year in both sex groups. The annual incidence rate (per 10,000 person years) ranged from 1.62 to 2.02 (female: 2.30⁻3.14; male: 0.71⁻1.17) from 2003 to 2011. City area had lowest incidence rate of RA compared with suburban or rural area. Higher incidence of RA was observed among lower socioeconomic status. The prevalence of RA was rising from 0.07% in 2001 to 0.14% in 2011. Incidence was about 2/10,000 person-years and female to male ratio was 5:1. Lower socioeconomic status and living rural region might be a risk factor for developing RA.