Role of 7-Joint Ultrasonic Score in Predicting the Prognosis of Rheumatoid Arthritis

Background: There is a higher possibility for rheumatoid arthritis (RA) recurrence if patients have subclinical synovitis. Seven-joint ultrasonic score (US7 score) allows an accurate detection of subclinical synovitis, but its predictive role in the recurrence of RA patients in remission is uncertain. Objectives: The goal of this study was to explore the role of US7 score in predicting the recurrence of RA patients with disease in clinical remission. Patients and Methods: Totally, 186 RA patients in clinical remission were recruited and their demographic and clinicobiologic characteristics were collected. The US7 score and disease activity score in 28 joints (DAS28) were recorded as baseline indicators for a 1-year follow-up. Patients were divided into the recurrence group and non-recurrence group according to their recurrent results. The clinical indicators and US7 scores before the follow-up were compared and analyzed between the two groups. Kaplan-Meier and univariate COX regression analysis were used to analyze the effect of US7 score on the recurrence of RA. Receiver-operating characteristics (ROC) curves were established to evaluate the predictive accuracy of DAS 28 and US7 score for the outcome of RA. Results: Of the186 RA patients, 55.9% received conventional disease-modifying antirheumatic drugs (cDMARD5) and 44.1% received biologic disease-modifying antirheumatic drugs (bDMARD5). Totally, 60 patients (32.3%) suffered from recurrence and were included in the recurrence group, and the remaining126 patients were included in the non-recurrence group. The recurrence rate of patients without subclinical synovitis (10.26%) was lower than that of patients with subclinical synovitis (48.15%, chi(2) = 27.556, P < 0.001). US7 score was associated with an increased risk of recurrence in RA patients after successful treatment (P < 0.001, hazard ratio =1.363, 95% CI =1.247 - 1.488). The area under the curve of the prediction model with combined US7 score and DAS 28 was higher (0.904) compared to that of US7 score or DAS 28 (P < 0.05). Conclusion: The US7 score is capable of predicting the recurrence of RA patients because of its advantages in identifying subclinical synovitis. The combined model of DAS28 and US7 score was accurate for predicting the recurrence of RA patients in clinical remission.