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.
“We know that if we treat patients early they do better, not only in the short term but also in the long term,” said Dr. Andrew Filer.
“The trouble is, not all patients come through the door with a confirmed diagnosis of rheumatoid or psoriatic arthritis,” explained the senior lecturer at the University of Birmingham.
Dr. Filer reported the preliminary results of a prospective study assessing the use of the imaging method. Specifically, the ongoing study is designed to determine whether musculoskeletal ultrasound can help determine which patients with very early arthritis actually develop rheumatoid arthritis (RA) or related conditions.
For the study, 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 rheumatoid arthritis, 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 five 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 of the wrist, metacarpophalangeal (MCP) and MTP regions was the best predictor of joint involvement, improving upon clinical predictive models for RA.
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.
Dr. Andrew Filer (left) reported that ultrasound of the wrist, MTP and MCP regions was the best predictor of joint involvement.
Source Courtesy Dr. Andrew Filer
My Take
A Pattern of Early Changes Needs to 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 poly-arthritis 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 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. Magnetic resonance imaging 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 course. Such studies are needed to better define the role of ultrasound in assessment of patients with early undifferentiated inflammatory arthritis and the role of diagnostic ultrasonography in routine clinical practice.
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.
