Assess Fewer Joints with Ultrasound to Watch RA Remission

Naredo E, Valor L, de la Torre I, et al., Ultrasound Joint Inflammation in Rheumatoid Arthritis in Clinical Remission: How Many and Which Joints Should Be Assessed?Arthritis Care Res, (2013) 65:512–517. doi:10.1002/acr.21869

In recent years, B-mode ultrasound (US) examination has proven more sensitive than comprehensive examination of 44 key joints for determining remission in rheumatoid arthritis (RA). Now, a cross-sectional study from Spain suggests that even with ultrasound, less may be more. Evaluating fewer and more targeted foot and hand joints with B-mode and power Doppler (PD) ultrasound proves just as effective as the broader joint assessment in detecting clinical remission.

The first study of its kind was conducted among 67 consecutive rheumatology clinic outpatients (50 women, 17 men, with an average age around 60) in Madrid. The patients had had RA for a mean  of 7.5 years, judged by 1987 ACR criteria, and had been treated with corticosteroids or DMARDs such as methotrexate for at least two years.

Clinical remission was defined as no disease flares or therapy changes in the previous six months.

Patients were evaluated for disease activity according to the Disease Activity Score in 28 joints (DAS28) and the Simplified Disease Activity Index (SDAI. They were then assessed with B-mode and PD US for joint inflammation in the hands and feet by a rheumatologist blinded to their clinical, laboratory, and radiographic data.

The study found the highest correlation with the 44-joint assessment for a limited US assessment of the bilateral wrist, metacarpophalangeal (MCP) joints, ankle, and metatarsophalangeal (MTP) joints 2-5, and a 12-joint assessment (also a combination of small and large joints).
 
These more limited US evaluations also had the highest sensitivity for spotting clinical remission as defined by the DAS28 or SDAI, compared to the 44-joint joint assessment.

Other reduced joint assessment models (US examination of 7 and 6 joints) showed lower correlations with the comprehensive US 44-joint assessment, both for B-mode SH and synovial PD signals.