Ultrasound helps predict flare risk in patients with JIA
medwireNews: Ultrasound abnormalities during clinical remission are a strong signal of future flare risk in patients with juvenile idiopathic arthritis (JIA), suggest researchers.
“Irrespective of treatment, the risk of flare in [ultrasound]-positive versus [ultrasound]-negative patients was almost four times higher,” the team reports in the Annals of the Rheumatic Diseases.
They add: “If confirmed by further studies, [ultrasound] may offer a useful tool in stratifying the risk of flare in people with JIA.” In all, 44 joints in 88 patients, whose disease had been inactive for at least 3 months, were scanned for the abnormalities synovial hyperplasia, joint effusion, and power Doppler (PD) signal.
The scans were abnormal for at least one gray scale elementary lesion, with or without abnormal PD signal, in 38 (0.98%) of the total 3872 joints scanned, affecting 22.7% of patients.
Of the different types of JIA, the 15 patients with extended oligoarthritis and the 15 with rheumatoid factor-negative polyarthritis were more likely to test positive for ultrasound abnormalities than negative, at 35.0% versus 11.8% and 30.0% versus 13.2%, respectively.
During the 4 years of follow-up, 46.6% of patients had a disease flare, and the researchers report that this occurred among 75.0% of those who tested positive for ultrasound abnormalities, compared with 38.2% of those testing negative.
Indeed, ultrasound abnormalities predicted future flare with 65% accuracy and a specificity and sensitivity of 90% and 37%, respectively.
After accounting for the effects of DMARD therapy, which 65.9% of patients were receiving, ultrasound abnormalities predicted future flare with an odds ratio of 3.8.
“As expected, the vascularisation of the synovial membrane, detected by the combination of PD signal in an area of synovial hyperplasia, is the most reliable [ultrasound] finding for synovial inflammation,” notes the team.
Orazio De Lucia (ASST Centro Traumatologico Ortopedico G Pini-CTO, Milan, Italy) and fellow investigators report that, on average, patients without ultrasound abnormalities had a greater likelihood of remission than those without.
At 1 year, the probability was 94.1% for patients without ultrasound abnormalities versus 55.0% for those with abnormalities, giving a difference that remained significant after taking therapy into account.
There did not appear to be any significant difference in the probability of future relapse according to International League of Associations for Rheumatology (ILAR) categories or according to Wallace criteria, although the association between positive ultrasound and relapse was significant for patients with persistent oligoarthritis and the likelihood of relapsing in the presence of ultrasound abnormalities was numerically greater for patients in clinical remission or complete remission.
The team therefore advises that “in case of positive [ultrasound], a follow-up should be carried out regardless of both the ILAR and Wallace categories because of high probability of relapse (75%), while a negative result does not rule out the risk.”
They add that “patients with a clinical remission period around or less than a year should be followed more carefully since [an ultrasound]-positive result can confirm the flare.”
By Lucy Piper
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