Disease activity and severity in patients with rheumatoid arthritis: relations to socioeconomic inequality

The aim of this study was to investigate possible differences in measures on disease process, joint damage, health status and self-efficacy between patients with rheumatoid arthritis (RA) living in an affluent and in a less affluent area in the same city. We analyzed data collected on patients enrolled in a community-based register of patients with RA in Oslo, Norway. 246 patients were examined by questionnaire in 1994 and 133 patients were examined clinically in 1997. Measures on disease process, joint damage, health status and self-efficacy were compared between patients from two residential areas. There was no significant difference regarding joint counts, patients' or investigator's evaluation of disease severity, blood test results and number of joint replacements. Significant differences were observed for disability and for various dimensions of health measured by the arthritis impact measurement scales and the short form-36: patients in the less affluent area reported poorer health status. Patients in this area also showed significantly lower scores on the arthritis self-efficacy scale. Patients with RA in two socioeconomically different areas in Oslo thus were found to be equal regarding disease process and joint damage measures. However, in the measures reflecting physical and psychosocial health status, patients in the less affluent area seemed to be more seriously ill. They also showed less confidence in their ability to influence the disease. Even in a welfare society with universal access to health care the impact of a well-defined chronic disease seems to be closely linked to the patient's socioeconomic situation.