An ultrasound negative for subclinical synovitis in arthralgia patients: is it helpful in identifying those not developing arthritis?

Abstract

Objective To investigate the negative predictive value (NPV) of musculoskeletal-ultrasound (MSUS) in arthralgia-patients at risk for developing inflammatory arthritis (IA). Methods An MSUS examination of hands and feet was performed in arthralgia-patients at risk for IA in four independent cohorts. Patients were followed for one-year on the development of IA. Subclinical synovitis was defined as greyscale ≥ 2 and/or power Doppler ≥ 1. NPVs were determined and compared with the prior risks of not developing IA. Outcomes were pooled using meta-analyses and meta-regression analyses. In sensitivity analyses, MSUS-imaging of tender joints only (rather than the full US-protocol) was analyzed and ACPA-stratification applied. Results After one-year 78%, 82%, 77% and 72% of patients in the four cohorts did not develop IA. The NPV of a negative US was 86%, 85%, 82% and 90%, respectively. The meta-analysis showed a pooled non-IA prevalence of 79% (95%CI: 75%-83%) and a pooled NPV of 86% (95%CI : 81–89%). Imaging tender joints only (as generally done in clinical practice) and ACPA-stratification showed similar results. Conclusion A negative US result in arthralgia has a high NPV for not developing IA, which is mainly due to the high a-priori risk of not developing IA. The added value of a negative US (<10% increase) was limited.