Treatment of rheumatoid arthritis (RA) with tumour necrosis factor (TNF) antagonists changes the relationship between disease activity and progression of radiological joint damage ('disconnect'): patients who have little or no response of disease activity still show reductions in damage progression. In early RA, the COBRA strategy (combination of methotrexate and sulfasalazine with step-down prednisolone) has been shown to be equivalent to high-dose methotrexate and infliximab in suppressing damage progression (BeSt trial). We investigated whether COBRA treatment can also 'disconnect' disease activity and damage.
A meta-analysis combined data from the COBRA trial (COBRA vs sulfasalazine monotherapy) with that of two arms of the BeSt trial (COBRA vs sequential monotherapy). Linear regression related 1-year progression of damage (Sharp van der Heijde score) as a dependent variable with disease activity (time-averaged Disease Activity Score in 44 joints (DAS44) or C-reactive protein (CRP)), treatment strategy (COBRA or control) and their interaction (indicator of a disconnect) as independent variables. The main outcome was the pooled interaction term.
Complete data from 60-100% of patients were available. Before pooling, disease activity was the only (strongly) significant independent factor related to damage progression. The pooled interaction term was (weakly) significant: time-averaged DAS44×treatment interaction, one-sided p=0.027; time-averaged CRP×treatment interaction, one-sided p=0.044.
Changes in the relationship between disease activity and damage progression may not be limited to anti-TNF treatment, but a property of early, rapid and deep suppression of joint inflammation, also induced by conventional strategies that include glucocorticoids.