Association Between Socioeconomic Status and Comorbidities Among Patients With Rheumatoid Arthritis

Results of a Nationwide Cross-Sectional Survey

Anna Shin; Seunghwan Shin; Ji Hyoun Kim; You-Jung Ha; Yun Jong Lee; Yeong Wook Song; Eun Ha Kang


Rheumatology. 2019;58(9):1617-1622. 

In This Article

Abstract and Introduction


Objectives: We examined the association between socioeconomic status (SES) and comorbidity distribution among patients with RA.

Methods: Information on comprehensive health status of 1088 RA patients (weighted n = 612 303) was obtained from the 2007–2015 Korea National Health and Nutrition Examination Survey database. SES components were household equivalence income, education and area of residence. To minimize confounding by age, patients were stratified by median age (63 years). Age-adjusted odds ratio (OR) with 95% confidence interval (95% CI) was estimated, comparing weighted prevalence of individual comorbidities between low and high SES groups in each age stratum.

Results: Among RA patients aged <63 years (mean 49 years, 70% female), we observed age-adjusted associations of depression (OR 2.13, 95% CI 1.01, 4.53), depressive mood (OR 2.68, 95% CI 1.54, 4.65), suicide ideation (OR 3.01, 95% CI 1.79, 5.07), diabetes (OR 3.09, 95%CI 1.31, 7.29), obesity (OR 2.04, 95% CI 1.30, 3.20), hypertriglyceridemia (OR 2.36, 95% CI 1.28, 4.34) and osteoarthritis (OR 2.12, 95% CI 1.13, 3.99) with low income, of suicide ideation with low education (OR 2.25, 95% CI 1.14, 4.44), but no association of any comorbidities with area of residence. Unhealthy behavior patterns were comparable between low- and high-income groups but patients with low income reported a numerically higher rate of failed access to necessary healthcare services. We did not find any association between SES and comorbidities among those aged ≥63 years (mean 72 years, 83% female).

Conclusion: Among Korean RA patients aged <63 years, socioeconomic inequalities of multiple comorbidities in mental, cardiometabolic and musculoskeletal systems were found.


RA is a chronic autoimmune inflammatory disease leading to joint damage and functional impairment. However, affecting not only the joint but also the multi-organ systems by either the disease itself or adverse treatment effects, RA is associated with an increased risk of various comorbidities. In fact, this increased risk has been reported on almost all organ systems,[1] particularly the cardiovascular system.[2]

Socioeconomic status (SES) is a well-known predictor of health outcome, as evidenced by higher mortality in low-SES populations.[3,4] RA patients have up to a 3-fold risk of mortality compared with the general population.[5] This risk is largely attributed to extra-articular comorbidities.[2] Therefore, the effect of SES on RA-related comorbidities has a high clinical importance. Studies on the relationship of RA and SES have consistently shown that low SES is associated with an increased risk of RA development, high disease activity, functional disability and mortality.[6,7] However, few studies comprehensively examine the multi-system effect of SES on RA-related comorbidities.

In this study, we aim to systematically investigate SES-related comorbidity inequalities among RA patients using the Korea National Health and Nutrition Examination Survey (KNHANES).