Secular changes in the progression of clinical markers and patient-reported outcomes in early rheumatoid arthritis

Abstract

Objectives: To examine secular trends in the progression of clinical and patient-reported outcomes in early RA.

Methods: A total of 2701 patients recruited to the Early Rheumatoid Arthritis Study or Early Rheumatoid Arthritis Network with year of diagnosis from 1986 to 2011. The 5-year progression rates for patients diagnosed at different points in time were modelled using mixed-effects regression; 1990, 2002 and 2010, were compared. Clinical markers of disease included the 28-joint count DAS and the ESR. Patient-reported markers included the HAQ, visual analogue scale of pain and global health, and the Short-Form 36.

Results: Statistically significant improvements in both 28-joint count DAS and ESR were seen over the 5 years in patients diagnosed with RA compared with those diagnosed earlier. By 5 years, 59% of patients with diagnosis in 2010 were estimated to reach low disease activity compared with 48% with diagnosis in 2002 and 32% with diagnosis in 1990. Whilst HAQ demonstrated statistically significant improvements, these improvements were small, with similar proportions of patients achieving HAQ scores of ≤1.0 by 5 years with a diagnosis in 1990 compared with 2010. Levels of the visual analogue scale and the Mental Component Scores of the Short-Form 36 indicated similar, statistically non-significant levels over the 5 years, irrespective of year diagnosed.

Conclusion: This study demonstrates improvements in inflammatory markers over time in early RA, in line with improved treatment strategies. These have not translated into similar improvements in patient-reported outcomes relating to either physical or mental health.

Keywords: cohort studies; inflammatory arthritis; longitudinal analysis; patient-reported outcomes.