Patients with rheumatoid arthritis (RA) with lower socioeconomic status (SES) are known to have more severe disease, more comorbidity, and higher mortality. It is not known whether SES influences response to treatment in RA. We examined the relationship between area of residence (as a surrogate for SES) and baseline outcome measures and response to treatment, using data from the British Rheumatoid Outcome Study Group randomized controlled trial of aggressive versus symptomatic treatment of long-standing, stable RA.
A total of 466 patients from 5 centers were recruited to the trial. Baseline data included age, sex, smoking status, and comorbidity. Patients were assigned a Townsend score (a measure of social deprivation) according to their area of residence. Outcome measures including the Disease Activity Score (DAS28), Health Assessment Questionnaire, Medical Outcomes Study Short Form-36, and EuroQol (EQ5D) were recorded at the beginning and end of the 3 year trial. The baseline, 3 year values, and change data were examined by Townsend quintile adjusting for each treatment arm.
Significant relationships between increasing social deprivation by area of residence and higher disease activity, higher pain, poorer physical function, poorer emotional aspects of mental health, and lower quality of life were found at baseline (adjusted for age, sex, disease duration, current smoking, treatment center, and treatment group). During the 3 year trial period, patients from the most deprived areas showed greater improvement, with statistically significant greater improvement on DAS28 (p = 0.041) and 28 tender joint count (p = 0.015).
Area of residence is related to the severity of RA at recruitment and is a predictor of response in a clinical trial situation. The results suggest that measures of SES should be recorded for patients enrolled in clinical trials, longitudinal observational studies, and in the clinical setting.