Combining High-Frequency Ultrasound With Anti-CCP Testing for Early RA Diagnosis

High[ALH1] -frequency color Doppler ultrasonography (HCDU) together with anti-cyclic citrullinated peptide (anti-CCP) antibody testing may allow for earlier diagnosis of rheumatoid arthritis (RA), as indicated by results from a study published in Experimental and Therapeutic Medicine.

Results from the study conducted in the Department of Rheumatology and Immunology, Yantai Yuhuangding Hospital, Shandong, China, show that combining HCDU and anti-CCP tests leads to 98.5% diagnostic specificity (P <.05). CCP antibody testing had 82.4% specificity and 72.7% sensitivity, whereas HCDU showed 83.8% specificity and 71.1% sensitivity. The sensitivity of both tests in combination was 47.3% (P <.05).

More accurate early tests are needed for the diagnosis of RA to prevent irreversible joint damage and permanent disabilities.

“Anti-CCP testing is standard in early diagnosis of [RA]. HCDU testing is not, although many rheumatologists do use it. We should probably be doing it more often if we can find erosions early on in disease,” Aruni Jayatilleke, MD, an assistant professor of medicine in the Division of Rheumatology at Drexel University College of Medicine, Philadelphia, Pennsylvania, told Rheumatology Advisor. Dr Jayatilleke, who was not a study author on the article, said the findings will not change current clinical practice. A total of 80 patients (aged 21-68 years), with a total of 162 affected joints, and 50 healthy individuals were enrolled in the current study from January to December 2015.

Anti-CCP antibody had 73.8% and 10% positive rates, and 26.2% and 90% negative rates in the study and control groups, respectively.

Positive anti-CCP antibody testing suggests a patient is more likely to develop joint damage during the course of their illness, said Dr Jayatilleke.

HCDU examinations showed that the joint most affected by RA was the metacarpophalangeal joint (16.7%), followed by the proximal interphalangeal joint (14.1%) and the metacarpophalangeal joint in the index finger (13.5%).

“[A] combination of HCDU examination and anti-CCP antibody testing can be considered useful to improve the early diagnostic rate of RA,” the researchers concluded. “HCDU examination is a sensitive, secure, atraumatic, and easily-operated diagnostic method for early RA patients with finger joint damage. Comned with anti-CCP antibody testing, it will provide a better chance for RA patients, and give them hope for a better treatment and improved prognosis.”

Dr Jayatilleke noted that larger studies are needed with more details about patient diagnosis.”If the tests are to be compared in diagnosis of early RA, we should look at patients without joint damage on X-ray, and see how good HCDU is at finding evidence of disease,” he said.

Erin Bauer, MD, a rheumatologist at Virginia Mason Medical Center in Seattle, Washington, told Rheumatology Advisor that future studies should examine the usefulness of HCDU in patients with early RA and negative CCP results, as those patients are more difficult to diagnose. Other studies should examine the outcomes in patients who are CCP positive, and in whom HCDU examination is conducted, to assess remission rates. “Adding HCDU (which has a low risk to the patient and which is usually cheaper than an MRI) is a reasonable way to rule out [RA] in patients who are CCP negative,” Dr Bauer said. “I don’t think this study alone should or will change clinical practice, but in general we are still learning how to best use HCDU in our RA patients.”

Summary & Clinical Applicability

Combining HCDU with anti-CCP antibody testing may allow early diagnosis of RA, which may allow for improved prognosis, as delayed diagnosis can lead to irreversible joint damage and permanent disabilities.

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