Subclinical synovitis detected by magnetic resonance imaging and ultrasonography following clinical remission in patients with rheumatoid arthritis:A retrospective study

Background:Subjective residual symptoms persist after clinical remission of rheumatoid arthritis(RA)in Japanese patients.Few studies have examined the relationship between these symptoms and subclinical inflammation using high-sensitivity imaging(musculoskeletal ultrasound[MSUS]and magnetic resonance imaging[MRI]).We examined the relationship between subjective residual symptoms and imaging findings in patients with RA who achieved clinical remission.Methods:We enrolled 30 patients with RA.The primary endpoint was the patients'subjective residual symptoms.The secondary endpoint was the relationship between the aforementioned symptoms and imaging findings.Results:Despite a mean Simplified Disease Activity Index of 1.3,imaging evaluation revealed inflammatory findings.In the multivariate analysis,the Health Assessment Questionnaire Disability Index(HAQ-DI)and pain visual analog scale(VAS)scores were extracted as independent related factors of subjective residual symptoms.The stratified analysis according to HAQ-DI showed a significant difference in synovitis on MRI between patients with and without residual disability(12.0±8.7 vs.5.3±5.3,respectively;p=0.0192).However,MSUS scores showed no significant difference in these two groups.In addition,no significant differences were found in MSUS and MRI scores between patients with and without residual pain VAS.Conclusions:Our findings demonstrated residual synovitis related to patientreported outcomes in patients with RA who achieved clinical remission.In particular,patients with an HAQ-DI score of>0.25 even after achieving clinical remission should be further examined by MRI and/or MSUS for the evaluation of residual synovitis.