Acknowledgement
The authors acknowledge the invaluable contributions of all KORean Observational study Network for Arthritis (KORONA) investigators.
References
- Breedveld FC, Combe B. Understanding emerging treatment paradigms in rheumatoid arthritis. Arthritis Res Ther 2011;13 Suppl 1(Suppl 1):S3.
- Malaviya AP, Ostor AJ. Rheumatoid arthritis and the era of biologic therapy. Inflammopharmacology 2012;20:59-69.
- Tatangelo M, Tomlinson G, Paterson JM, et al. Association of patient, prescriber, and region with the initiation of first prescription of biologic disease-modifying antirheumatic drug among older patients with rheumatoid arthritis and identical health insurance coverage. JAMA Netw Open 2019;2:e1917053.
- Schmajuk G, Trivedi AN, Solomon DH, et al. Receipt of disease-modifying antirheumatic drugs among patients with rheumatoid arthritis in Medicare managed care plans. JAMA 2011;305:480-486.
- Codreanu C, Popescu CC, Mogosan C. Area of residence and socioeconomic factors reduce access to biologics for rheumatoid arthritis patients in romania. Biomed Res Int 2018;2018:7458361.
- Molina E, Del Rincon I, Restrepo JF, Battafarano DF, Escalante A. Association of socioeconomic status with treatment delays, disease activity, joint damage, and disability in rheumatoid arthritis. Arthritis Care Res (Hoboken) 2015;67:940-946.
- Margaretten M, Barton J, Julian L, et al. Socioeconomic determinants of disability and depression in patients with rheumatoid arthritis. Arthritis Care Res (Hoboken) 2011;63:240-246.
- Jacobi CE, Mol GD, Boshuizen HC, Rupp I, Dinant HJ, Van Den Bos GA. Impact of socioeconomic status on the course of rheumatoid arthritis and on related use of health care services. Arthritis Rheum 2003;49:567-573.
- DeWitt EM, Lin L, Glick HA, Anstrom KJ, Schulman KA, Reed SD. Pattern and predictors of the initiation of biologic agents for the treatment of rheumatoid arthritis in the United States: an analysis using a large observational data bank. Clin Ther 2009;31:1871-1880; discussion 1858.
- Camacho EM, Verstappen SM, Symmons DP. Association between socioeconomic status, learned helplessness, and disease outcome in patients with inflammatory polyarthritis. Arthritis Care Res (Hoboken) 2012;64:1225-1232.
- Kotyla PJ. Bimodal function of anti-TNF treatment: shall we be concerned about anti-TNF treatment in patients with rheumatoid arthritis and heart failure? Int J Mol Sci 2018;19:1739.
- Dixon WG, Watson K, Lunt M, Hyrich KL, Silman AJ, Symmons DP. Rates of serious infection, including site-specific and bacterial intracellular infection, in rheumatoid arthritis patients receiving anti-tumor necrosis factor therapy: results from the British Society for Rheumatology Biologics Register. Arthritis Rheum 2006;54:2368-2376.
- Alder NE, Snibbe AC. The role of psychosocial processes in explaining the gradient between socioeconomic status and health. Curr Dir Psychol Sci 2003;12:119-123.
- Verstappen SMM. The impact of socio-economic status in rheumatoid arthritis. Rheumatology (Oxford) 2017;56:1051-1052.
- Chiu H, Hollingworth S, Van Driel M, Magin P, Benham H. Under-reporting of socio-economic status in randomized control trials of biologic disease-modifying anti-rheumatic drugs in rheumatoid arthritis. Rheumatology (Oxford) 2017;56:660-661.
- Sung YK, Cho SK, Choi CB, et al. Korean Observational Study Network for Arthritis (KORONA): establishment of a prospective multicenter cohort for rheumatoid arthritis in South Korea. Semin Arthritis Rheum 2012;41:745-751.
- Arnett FC, Edworthy SM, Bloch DA, et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 1988;31:315-324.
- Rothman KJ, Greenland S, Walker AM. Concepts of interaction. Am J Epidemiol 1980;112:467-470.
- Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40:373-383.
- Dey M, Busby A, Elwell H, et al. Association between social deprivation and disease activity in rheumatoid arthritis: a systematic literature review. RMD Open 2022;8:e002058.
- Bergstra SA, Branco JC, Vega-Morales D, et al. Inequity in access to bDMARD care and how it influences disease outcomes across countries worldwide: results from the METEOR-registry. Ann Rheum Dis 2018;77:1413-1420.
- Baek YH, Shin JY. Trends in polypharmacy over 12 years and changes in its social gradients in South Korea. PLoS One 2018;13:e0204018.
- Kim JH, Lee SG, Lee KS, Jang SI, Cho KH, Park EC. Impact of health insurance status changes on healthcare utilisation patterns: a longitudinal cohort study in South Korea. BMJ Open 2016;6:e009538.
- Pampel FC, Krueger PM, Denney JT. Socioeconomic disparities in health behaviors. Annu Rev Sociol 2010;36:349-370.
- Sriram S, Khan MM. Effect of health insurance program for the poor on out-of-pocket inpatient care cost in India: evidence from a nationally representative cross-sectional survey. BMC Health Serv Res 2020;20:839.
- Kangovi S, Barg FK, Carter T, Long JA, Shannon R, Grande D. Understanding why patients of low socioeconomic status prefer hospitals over ambulatory care. Health Aff (Millwood) 2013;32:1196-1203.
- Kalkan A, Roback K, Hallert E, Carlsson P. Factors influencing rheumatologists' prescription of biological treatment in rheumatoid arthritis: an interview study. Implement Sci 2014;9:153.