Association between ultrasound images and patient-reported outcomes in the treatment of rheumatoid arthritis: a retrospective study

Background Improvements in the treatment of rheumatoid arthritis (RA) have made it possible to achieve treatment goals. It has been reported that both residual synovitis caused by RA and the patients' subjective symptoms remain even after achieving the treatment goals; however, there are limited reports showing a relationship between them. Furthermore, no studies have evaluated the relationship between patient-reported outcomes (PROs) and subclinical synovitis measured by musculoskeletal ultrasonography (MSUS) in the treatment of RA. This study aimed to investigate residual symptoms and residual synovitis due to remission (REM) or low disease activity (LDA). Methods We performed MSUS on 300 patients with RA who attended our hospital for routine care, and we analysed them cross-sectionally by disease activity. Grayscale (GS) and power Doppler (PD) synovitis was evaluated in 22 bilateral hand joints using MSUS. We first performed univariate and multivariate analysis by dividing the data by disease activity. Next, we analysed each PRO in the obtained MSUS results. Results A multivariate analysis of high disease activity (HDA)/moderate disease activity (MDA) vs. LDA/ REM group identified tender joint count (TJC), pain visual analog scale (VAS) score, and presence or absence of GS score >= 2. The one-way analysis of the relationship between the presence or absence of GS score >= 2 and each PRO showed a significant difference. In contrast, a multivariate analysis of LDA vs. REM group identified TJC and fatigue VAS score. In REM, PROs alone were relevant, and there was no correlation with MSUS. Conclusion We found that the residual inflammation in the ultrasound images was associated with PROs in the LDA group, but not in the REM group. Trial registration Retrospectively registered.