Repair of erosions occurs almost exclusively in damaged joints without swelling

Background Negative radiographic change scores obtained under blinded time-sequence conditions suggest that repair of joints may indeed occur. It is likely that, if repair truly exists, it would be preferentially seen in clinically inactive joints from patients treated with drugs with well-known structural efficacy. Objective To determine whether repair is associated with both the absence or improvement of swelling and with treatment. Patients and methods Radiographs from patients of the TEMPO trial were scored twice by two readers according to the Sharp-van der Heijde score, blinded to both treatment and true time sequence. Single-joint change scores in erosions were coupled with single-joint swelling scores obtained from clinical examination. Consistency of observed improvement across readers and repeat reads was described, and factors expected to increase the likelihood of occurrence of both worsening and improvement of erosion were tested by generalised estimating equations (GEE) modelling. Results In all of the four independent reads, the mean change in erosion score was statistically significantly negative only in the subgroup of joints with absent or improved swelling, when erosions were present at baseline. Multivariate analysis showed that worsening of the erosion score in a joint was significantly increased if that joint was already damaged at study entry, clinical swelling persisted and methotrexate was used instead of etanercept. Repair was associated with improvement of swelling and use of etanercept (p <= 0.007 for all associations). Conclusion Repair of erosions almost exclusively occurs in joints with improvement or absence of swelling, in patients treated with etanercept. Progression is seen more frequently in joints with persistent swelling, in patients receiving methotrexate monotherapy, primarily if damage is already present.