Background To decrease burden of disease of rheumatoid arthritis (RA) we need to identify patients at risk for RA as early as possible, preferably as no clinical apparent synovitis could be detected yet. Previous studies suggest that this should be in the arthralgia phase or even before that. Up to now it has been fairly difficult to identify those arthralgia patients who develop inflammatory arthritis (IA), but recent studies in ultrasound (US) suggest that earlier detection is possible .
Objectives We aim to identify which arthralgia patients will develop clinical apparent IA within a year using US to detect subclinical synovitis at first consultation.
Methods In a multi-centre prospective cohort study we followed arthralgia patients with ≥2 painful joints of hands, feet or shoulders without clinical apparent synovitis. Patients had a symptom duration of <1 year which could not be explained by other conditions (e.g. fibromyalgia). We collected data at baseline, 6 months and 12 months follow-up, which included physical examination, laboratory variables (ESR, CRP, auto-antibodies), diagnosis and medication used (including DMARDs at 6 and 12 months). At baseline we examined patients by US, which included 26 joints (MCP2–5, PIP2–5, wrists, MTP2–5) graded on greyscale (GS; 0–3) and power Doppler (PD; 0–3) according to a semi-quantitatively scoring system of Naredo et al. US synovitis was defined as GS grade 2 or 3 and/or PD grade 1, 2 or 3. After one year follow-up we determined the incidence of IA (clinical soft tissue swelling or start of DMARD treatment). We performed a complete-case analysis. For univariate logistic regression we tested demographic characteristics, clinical characteristics, and ultrasound findings and their association for development of IA. For multivariate logistic regression we selected the strongest variables (p<0.2).
Results In total, 196 patients were included of whom 154 completed the 12 months follow-up. At baseline 72 (38%) arthralgia patients had US synovitis and in 29 (15%) patients a positive PD signal was detected. At 12 months follow-up 36 (23%) patients had developed IA of whom 22 patients initiated DMARD treatment. Table 1 shows baseline characteristics of cases and non-cases and the results of the univariate analysis. Strongest variables were ACPA, RF, morning stiffness >30 minutes and PD signal. In the multivariate logistic regression positive ACPA (OR 4.56: 95% CI 1.26–16.46) and the presence of PD signal (OR 5.79: 95% CI 1.75–19.19) at baseline were associated with the development of IA during one year follow-up.
Conclusions In this early arthralgia cohort 38% of patients showed US synovitis at baseline. At 12 months 23% of the patients developed IA. In a multivariate analysis positive PD signal and positive ACPA were significantly associated with the development of IA after one year.
Colebatch AN, Edwards CJ, Ostergaard M, van der Heijde D, Balint PV, D'Agostino MA, et al. EULAR recommendations for the use of imaging of the joints in the clinical management of rheumatoid arthritis. Ann Rheum Dis. 2013 Jun;72(6):804–14.
Disclosure of Interest None declared