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Ultrasound speeds new RA diagnoses

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Ultrasound helps early diagnosis in challenging cases

The main issue when imaging joints in patients with suspected rheumatoid arthritis (RA) or early disease is: What does imaging add to a standard clinical examination? Standard x-rays do not show many erosions in patients with early disease; ultrasound, as well as MRI, are much more sensitive. Both ultrasound and MRI can be very helpful for difficult-to-diagnose cases. In my experience, about 5%-10% of early-diagnosis cases benefit from using ultrasound or MRI imaging of joints.


Dr. Philip Conaghan

Ultrasound is more widely used than MRI is and also costs less. You can examine multiple joints with ultrasound, you don’t need to inject contrast, and you can also use the ultrasound to guide injections. For all these reasons, ultrasound has rapidly become widely used to aid early diagnoses. But not every clinician has the expertise to perform ultrasound examinations, and it has not yet been definitively proven that using ultrasound routinely for diagnostically challenging cases is cost effective. I suspect it is cost effective to perform ultrasound examinations fairly broadly on patients suspected of having RA, compared with the financial and social costs of delayed RA diagnosis in which the patient goes untreated for an added period of time, but study results are still needed to prove this.

In June, I chaired a task force that issued the European League Against Rheumatism’s first recommendations on using joint imaging in the management of RA (Ann. Rheum. Dis. 2013;72:804-14). The 10 recommendations made by the task force include several that support and encourage the use of ultrasound or MRI for both the initial diagnosis of RA as well as subsequent management. However, because evidence is currently lacking to fully document the feasibility, cost, and training required to use methods like ultrasound in routine practice, our recommendations could not be unqualified. For example, our first recommendation says, "When there is diagnostic doubt, conventional radiography, ultrasound, or MRI can be used to improve the certainty of a diagnosis of RA above clinical criteria alone." The level of evidence for this recommendation is level III, which is not the highest level. In addition, note that the recommendation says "can be used" rather than mandating the use of ultrasound or another imaging method. In the same way, our third recommendation says, "Ultrasound and MRI are superior to clinical examination in the detection of joint inflammation; these techniques should be considered for more accurate assessment of inflammation." Again, the level of evidence, III, precluded us from saying anything more definitive than "should be considered."

Philip G. Conaghan, M.B., Ph.D., is a professor of musculoskeletal medicine at Leeds (U.K.) University. He said that he is a speaker on behalf of or an advisor to Bristol-Myers Squibb, Pfizer, and Roche. He made these comments in an interview.


 

AT THE EULAR CONGRESS 2013

MADRID – Routine joint scans by ultrasound in patients with suspected rheumatoid arthritis led to faster diagnoses and quicker initiation of disease-modifying treatment in a multicenter-study of more than 250 patients.

But the results did not address whether this earlier diagnosis and treatment produced better outcomes. "While earlier diagnosis and treatment is known to lead to better outcomes, a large, prospective study is required to explore the long-term clinical impact and cost effectiveness of wider routine use of ultrasound by rheumatologists," Dr. Stephen Kelly said at the annual European Congress of Rheumatology.

Despite this current limitation of the available evidence, Dr. Kelly is convinced of the value of routine ultrasound examinations for joint assessment in patients with possible rheumatoid arthritis (RA). "You can see raging inflammation in joints that are not swollen or tender," he said in an interview. The discrepancy between clinical symptoms and the ultrasound appearance can be "surprising," said Dr. Kelly, a rheumatologist at Mile End Hospital in Barts Health NHS Trust in London.

Dr. Stephen Kelly

The current study involved observation of patients referred by primary-care physicians to rheumatologists at four U.K. hospitals. Each of the four sites selected included some rheumatologists who routinely used ultrasound and others who did not. By the end of the study, 134 patients had been assessed with ultrasound joint examinations and 124 had been assessed without ultrasound. All patients were initially seen in the referral rheumatology clinics an average of 5 months after symptom onset. They had a mean age of about 53 years, and about 70% were women.

Among the 134 patients assessed initially with ultrasound, the average time to a formal RA diagnosis was 2.24 months, and the median time was 0.89 months. Among the patients not examined with ultrasound, a formal RA diagnosis was made at a mean of 2.76 months and a median of 2 months. These differences were statistically significant.

The investigators eventually diagnosed RA in 54 of the patients assessed with ultrasound and in 58 patients assessed without ultrasound. The median time to the start of treatment with a disease-modifying antirheumatic drug (DMARD) was 0.62 months among patients routinely examined with ultrasound and 1.41 months among those examined without ultrasound.

Put another way, among the patients eventually diagnosed with RA, 67% were diagnosed within a month of initial referral when their rheumatologists routinely used ultrasound, compared with 37% of the RA patients diagnosed within the first month when ultrasound wasn’t used. Initiation of DMARD treatment for the subgroup eventually diagnosed with RA happened in the first month for 63% of the patients routinely assessed by ultrasound, and in 32% of those worked-up without ultrasound.

In a further analysis, the rheumatologists who assessed 134 patients with ultrasound were asked whether their use of ultrasound made a difference. Fifty-three percent said that the first scan they obtained was instrumental in making their diagnosis, and 39% said that a subsequent ultrasound exam was critical in their diagnostic process.

The researchers also asked the rheumatologists who used ultrasound whether the ultrasound results played an important role in management decisions. Thirty-eight percent of the rheumatologists said that the first ultrasound scan they obtained played an important role in their management decisions, and 57% said that a subsequent ultrasound scan affected management.

The study was sponsored by AbbVie. Dr. Kelly said that he had no personal disclosures.

mzoler@frontlinemedcom.com

On Twitter @mitchelzoler

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