Major Finding: Musculoskeletal ultrasound of the wrist, as well as the metacarpophalangeal and metatarsophalangeal regions, showed the highest predictive value in very early arthritis patients.

Data Source: A prospective study of 58 patients with very early arthritis.

Disclosures: Dr. Filer had no conflicts of interest in relation to the study. The study was funded by Arthritis Research UK and the AutoCure Consortium.

BIRMINGHAM, ENGLAND — Musculoskeletal ultrasound of multiple small joints is more accurate than traditional clinical assessment at predicting patient outcomes in very early arthritis, judging from the results of a pilot investigation.

“Musculoskeletal ultrasound is not routinely used for diagnosing arthritis [in the United Kingdom],” according to Dr. Andrew Filer, who noted that there have been few studies of the technique for the prediction of patient outcome.

“We know that if we treat patients early they do better, not only in the short term but also in the long term,” he added. “The trouble is, not all patients come through the door with a confirmed diagnosis of rheumatoid or psoriatic arthritis,” said Dr. Filer, who is senior lecturer at the University of Birmingham and consultant rheumatologist at Sandwell and West Birmingham Hospitals NHS Trust. He is also a member of the Rheumatology Research Group at the University of Birmingham.

At the meeting, Dr. Filer reported the preliminary results of an ongoing study designed to determine if musculoskeletal ultrasound can help predict which patients with very early arthritis actually develop rheumatoid arthritis (RA) or related conditions.

The researchers recruited 58 patients who had inflammatory joint symptoms of 3 months or less duration and clinically apparent inflammation of at least one joint. Half of the cohort (50%, 29) had RA, with 48% (14) having detectable anti-citrullinated peptide antibodies. Sixteen (27.6%) patients had resolving arthritis, which was mostly unclassified, and 13 (22.4%) patients had persistent conditions other than RA.

The non-RA group included five patients with psoriatic arthritis, one with reactive arthritis, and two with systemic lupus erythematous. Disease could not be classified in 5 patients.

Patients were assessed clinically before undergoing musculoskeletal ultrasound within 24 hours, and followed up prospectively for 18 months. Baseline and follow-up clinical assessments included 68 tender and 66 swollen joint counts; 28-joint disease activity score; serological data; and conventional radiography of the hands and feet.

An ultrasonographer, who was unaware of the clinical findings, systematically assessed a total of 50 joints using four-point semi-quantitative scales to note the presence of erosions.

Musculoskeletal ultrasound detected significantly more joint involvement than did clinical examination. It also detected more clinically silent involvement of the wrist, elbow, knee, ankle, and metatarsophalangeal (MTP) region.

Sensitivity and specificity analyses showed that ultrasound images of the wrist, metacarpophalangeal (MCP) region, and MTP region were the best predictors of joint involvement, improving upon clinical predictive models for RA. In contrast, imaging of the large joints was not useful for predicting joint involvement.

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Dr. Andrew Filer demonstrates ultrasound assessment of the wrist and metacarpophalangeal region.

Source Courtesy Dr. Andrew Filer

My Take

Patterns of Very Early Changes Must Be Confirmed

The study provides an indication that systematic evaluation of joints by ultrasound in patients presenting with very early undifferentiated arthritis may be a useful predictor of future diagnosis of rheumatoid arthritis. Ultrasound may detect involvement in more joints than are detected on clinical examination, and it may detect early erosions with greater sensitivity than conventional radiography. Especially in patients who do not have anti-citrullinated peptide antibodies, the presence of polyarthritis and erosions on ultrasound appears to herald an eventual diagnosis of RA even when patients who do not appear to have polyarthritis on clinical examination.

This approach has promise, but examination of 50 joints is not likely to be efficiently done or reimbursable in routine clinical practice. Further work may yield a profile of specific target joints that may have highest sensitivity and predictability for eventual development of RA when examined by ultrasound, or determine whether all joints would need to be evaluated. Studies of conventional radiography have failed to reveal a consistent pattern or joints that could be consistently excluded. MRI studies of the hands have suggested that involvement of specific joints in the wrists, for example, might best discriminate the eventual diagnosis of RA early in the disease Such studies are needed to better define the role of ultrasound in assessing patients with early undifferentiated inflammatory arthritis.

ERIC L. MATTESON, M.D., is professor of medicine and chief of the division of rheumatology at the Mayo Clinic, Rochester, Minn. He has no relevant financial disclosures.

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Ultrasound Predicted Outcomes of Early Arthritis