Background and objectives Remission is the optimum treatment target for rheumatoid arthritis (RA). Although clinical remission is increasingly achieved, patients can still progress both structurally and functionally. Furthermore, many patients are unable to sustain clinical remission. There is a need for more objective measures of the remission state and predictors of flare. We aimed to assess whether Power Doppler (PD) ultrasound could predict stability of remission in patients with RA.
Materials and methods 455 patients were selected from an inflammatory arthritis register based on a diagnosis of RA and with initially active disease who subsequently achieved a DAS28 score <2.6 at a single visit. 291 had a follow-up visit (minimum follow-up 12 months). A DAS28 >3.2 was considered as flare. Ultrasound data was available for 211 patients.
Results Stable remission over 12 months was not associated with demographic parameters with the exception of longer disease duration. Patients with early RA receiving conventional synthetic (csDMARDs) were less stable than patients (with established RA) receiving biologic therapy +/- DMARDs. With respect to ultrasound data, more PD signal was associated with the inability to maintain remission (p = 0.036). ROC curve analysis was 0.395 for PD. Grey-scale changes were not informative. Sustained remission was associated with the number of tender joints (p = 0.05).
Conclusion Demographic and clinical assessments (with the exception of tender joint counts) are not predictors of stable remission. A significant association with PD synovitis suggests that this is a more accurate measure of inflammation and characterisation of the remission state. This could potentially be used to predict flare in the clinical setting to help guide treatment.