Abstract
Background: Rheumatoid arthritis (RA) treat-to-target (T2T) regimens often use the disease activity score (28 joints) incorporating C-reactive protein (DAS28(CRP)) as an outcome measure. We compared changes in the DAS28CRP with changes in magnetic resonance imaging (MRI) inflammation on treatment escalation.
Methods: Eighty seropositive RA patients with active disease were enrolled. Group A (N = 57) escalated to another conventional disease-modifying therapy (cDMARD) combination, and Group B (N = 23) to anti-TNF therapy/cDMARDs. Contrast-enhanced 3T-MRI wrist scans were obtained before and 4 months after regimen change. Scan pairs were scored for inflammation (MRI(i)) and damage. Disease activity was assessed using the DAS28CRP.
Results: Eighty patients were enrolled and 66 MRI scan pairs were available for analysis. Intra-reader reliability was high: intraclass correlation coefficient (average) 0.89 (0.56-0.97). Delta DAS28(CRP) did not differ between groups: Group A, -0.94 (-3.30, 1.61); Group B, -1.53 (-3.59, 0.56) (p = 0.45). Delta MRI(i) also did not differ: Group A, 0 (-25, 10); Group B, -1 (-15, 28) (p = 0.12). Combining groups, Delta MRI(i) correlated weakly with Delta DAS28(CRP) (Spearman's 0.36, p = 0.003). Using multiple linear regression analysis adjusting for confounders, Delta DAS28(CRP) was associated with Delta MRI(i) (p = 0. 056). Of the individual MRI measures, only Delta tenosynovitis correlated with Delta DAS28(CRP) (Spearman's 0.33, p = 0.007). Delta MRI(i) was negatively associated with the MRI erosion score at entry (p = 0.0052).
Conclusions: We report the first study investigating the link between changes in clinical and imaging inflammation in a real-world RA cohort escalating to conventional and biologic DMARDs. The association was significant but relatively weak, suggesting that MRI targets cannot yet be advocated as outcomes for T2T escalation.