Time trends in disease activity, response and remission rates in rheumatoid arthritis during the past decade: results from the NOR-DMARD study 2000-2010

Objectives To investigate whether baseline disease activity levels and responses in patients with rheumatoid arthritis (RA) changed during the period 2000-2010. Methods Data were provided by the Norwegian disease-modifying antirheumatic drug (NOR-DMARD) study. Patients with inflammatory joint diseases starting new treatment with disease-modifying antirheumatic drugs (DMARDs) were consecutively included and followed longitudinally. Time trend analyses were performed in methotrexate (MTX)-naive RA patients starting MTX monotherapy (MTX mono) and biologic DMARD (bDMARD)-naive RA patients starting tumour necrosis factor inhibitors+MTX (TNFi+MTX). Results A total of 2573 patients were included in the analyses: MTX mono n=1866 (69.9% female, 62.0% RF+, mean (SD) age 56.0 (13.7) years, median (25-75 percentile) time from diagnosis 0.2 (0.01-2.8) years); TNFi+MTX n=707 (70.3% female, 75.0% RF+, mean (SD) age 52.1 (13.2) years, median (25-75 percentile) time from diagnosis 5.7 (2.0-13.7) years). Significant time trends towards lower baseline disease activity score 28 (DAS28) as well as other disease activity measures were found in both groups (DAS28 from 5.17 to 4.75 in MTX mono and from 5.88 to 4.64 in TNFi+MTX), and disease duration became shorter. Six-month DAS28 remission rates increased significantly over the years (from 17.8 to 37.6 in MTX mono and from 16.9 to 46.3 in TNFi+MTX). Conclusions During the last decade, baseline RA disease activity level at the time of starting MTX as well as TNFi+MTX decreased from high to moderate. A more than twofold increase in 6-month remission rates was observed in both groups. Our findings indicate that clinicians have implemented modern, more aggressive treatment strategies, which hopefully will lead to better long-term disease outcomes.