Background Although “clinical remission” has been a realistic goal of treatment in rheumatoid arthritis (RA), its definition is still controversial. In fact, progressive joint destruction is often observed even during persistent DAS28-based remission,12 suggesting that the criteria are not satisfactory for target of treatment. There is accumulating evidence that ultrasonography (US) is helpful for judgment of the disease remission.
Objectives Here we investigated whether US can predict Boolean remission in RA patients who had been satisfied with DAS28-based remission criteria.
Methods Twenty-seven RA patients who had been in DAS28-based clinical remission (DAS28-ESR < 2.6 or DAS28-CRP < 2.3) for more than 2 months were recruited and monitored for 2 years. Excluding patients having clinical flare-up during the study, the remaining patients were divided based on Boolean remission criteria at 2 years. Bilateral wrists and all of MCPs and PIPs were examined by Gray scale (GS) and power Doppler (PD) US at the entry. GS and PD signals were scored in each joint from 0 to 3, respectively. Total GS score and total PD score were calculated by summing up the score of individual joints. Hand X-ray was evaluated by van der Heijde-modified total Sharp score (mTSS) at the entry and end of study.
Results Five patients dropped out of the study due to clinical flare-up, while DAS28 remission had been maintained for 2 years in 22 patients, including 16 patients (73%) who met Boolean remission criteria at the end of study. Both total GS score and total PD score at baseline were significantly lower in Boolean remission group than non-remission group (7.75 ± 6.02 vs 16.0 ± 11.3, p = 0.012, and 1.06 ± 1.14 vs 6.33 ± 6.99, p = 0.020, respectively). There was no significant difference in other baseline parameters, including duration of disease, duration of remission, mTSS, and disease activity composite parameters between the two groups. The cut-off values for total GS and PD scores calculated from the ROC curves were total GS scores > 7 and total PD scores > 2. The area under the ROC curves for total GS and PD scores were 0.82 (95% CI = 0.60 to 0.95, p = 0.0004) and 0.82 (95% CI = 0.60 to 0.95, p = 0.013). Among the factors for Boolean remission criteria at 2 years, high patient global assessment score was associated with high total GS score at the entry, while high swollen joint count was related to high total PD score. On the other hand, progression of mTSS was associated with high total PD score, but not with total GS score, at the entry.
Conclusions This study shows that none or low grade of GS and PD findings in US are associated with the achievement of Boolean remission in near future. Thus, US is essential for assessment and prediction of “deeper remission” of RA.
Mulherin D, Fitzgerald O, Bresnihan B. Clinical improvement and radiological deterioration in rheumatoid arthritis: evidence that the pathogenesis of synovial inflammation and articular erosion may differ. Br J Rheumatol 1996;35:1263-8.
Molenaar ET, Voskuyl AE, Dinant HJ, et al. Progression of radiologic damage in patients with rheumatoid arthritis in clinical remission. Arthritis Rheum 2004;50:36-42.
Disclosure of Interest None Declared