Pain over 2 years after start of biological versus conventional combination treatment in early rheumatoid arthritis: results from the randomised controlled SWEFOT trial.

OBJECTIVE: To compare the pain course between methotrexate (MTX)-refractory early rheumatoid arthritis (RA) patients randomised to infliximab (IFX) versus sulfasalazine+hydroxychloroquine (SSZ+HCQ). METHODS: The randomised, controlled, open-label SWEFOT (SWedish FarmacOTherapy) trial enrolled new-onset RA patients Oct 2002-Dec 2005. After 3 months on MTX, patients not reaching low disease activity (28-joint Disease Activity Score; DAS28≤3.2) were randomised to adding IFX (n=128) or SSZ+HCQ (n=130) and followed for 21 months. Here, outcomes included area-under-the-curve (AUC) for Visual Analogue Scale (VAS) of pain, unacceptable pain (VAS pain>40mm [0-100]); and unacceptable pain despite inflammation control (refractory pain; VAS pain>40+C-reactive protein<10mg/L). Between-group differences were analysed with multivariate regression models. RESULTS: Overall, 50% of randomised patients (n=258) in the crude setting, reported unacceptable pain at randomisation, declining to 29% at 21 months (p<0.001), when refractory pain constituted 82% of all unacceptable pain. Comparing randomised arms (intention-to-treat analysis), AUC for VAS pain was lower in the MTX+IFX-group (p=0.01), and at 21 months 32% with MTX+IFX and 45% with MTX+SSZ+HCQ had unacceptable pain (adjusted relative risk 0.68 [95%CI:0.51-0.90]; p=0.008). Regarding refractory pain, no between-group differences were observed. CONCLUSION: Despite active combination treatment, almost 1/3 of new-onset RA patients reported unacceptable pain after 21 months and refractory pain constituted more than 4/5 of this pain load. Adding IFX versus SSZ+HCQ to MTX reduced both cumulative pain and unacceptable pain at 21 months, suggesting less long-term pain for the biological therapy. These results display insufficient effects of current treatment strategies on inflammation-independent pain components, warranting alternative approaches in affected patients.