Ultrasound in clinically suspect arthralgia: the role of power Doppler to predict rheumatoid arthritis development.

Objective: To determine the usefulness of power Doppler (PD) ultrasound (US) to predict rheumatoid arthritis (RA) development in patients with clinically suspect arthralgia (CSA).

Methods: Retrospective analysis of a US unit cohort over a 1-year period. Patients with CSA and no previous diagnosis of inflammatory arthritis (IA) were included for analysis. All underwent bilateral US examination of the hands and/or feet according to the EULAR guidelines. Active US inflammation was defined as PD synovitis and/or tenosynovitis ≥1 at any location. RA diagnosis according to clinician criteria 6 months after the US examination was checked. Univariate and multivariate logistic regression models were employed to investigate possible predictive factors of RA development.

Results: A total of 110 CSA patients (80 females, mean age 53.6 years) were included for analysis. After 6 months of follow-up, 14 (12.7%) developed RA and 34 (30.9%) IA. US active inflammation was present in 38 (34.5%) patients (28.2% showed PD synovitis and 18.2% PD tenosynovitis). Multivariate analysis showed that ACPA (OR 1.0003; 95% CI 1.002-1.006) and ESR (OR 1.054; 95% CI 1.016-1.094) were significantly associated with the detection of US active inflammation at baseline. Only PD tenosynovitis was found to be an independent predictive factor of an evolution towards RA (OR 6.982; 95% CI 1.106-44.057) and IA (OR 5.360; 95% CI 1.012-28.390).

Conclusion: US is able to detect features of subclinical inflammation in CSA patients, especially in those with higher ESR and ACPA values. Only PD tenosynovitis at baseline US assessment was found to be an independent predictor of RA and IA development in CSA patients.