Power Doppler ultrasonography (PDUS) may help measure response to TNF-blockers as well as predict X-ray progression in rheumatoid arthritis (RA) patients, according to a new study in the August issue of Arthritis & Rheumatism,1 which highlights yet another role for US monitoring in clinical rheumatology. Previous research has shown that PDUS is useful in measuring joint inflammatory activity in RA.
“These findings indicate that PDUS is a valid method for monitoring response to anti-TNF therapy in RA; results obtained by PDUS are reproducible and sensitive to change,” the study authors wrote. “PDUS findings may have predictive value in relation to radiological outcome.”
PDUS shows synovial response to TNF-inhibitors
The new study comprised 278 RA patients who underwent clinical, laboratory, and PDUS assessment at baseline and after 1, 3, 6, and 12 months of anti-TNF treatment. Researchers also conducted an X-ray assessment of the patients’ hands and feet at baseline and 12 months and recorded the Disease Activity Score in 28 joints (DAS28) at each visit. The PDUS examination included 86 intra-articular and peri-articular sites in 28 joints. The researchers also scored US count and index for both synovial fluid and hypertrophy in addition to PD signal score in all synovial sites. They assessed the sensitivity to change of the PDUS variables by estimating the smallest detectable difference (SDD) from the intra-observer variability.
The study showed a significant parallel improvement in DAS28 and PDUS parameters at follow-up assessment (P <.0005 for within-subject between-visit changes). Moreover, the SDD for PDUS parameters was lower than the mean changes throughout follow-up.
Time-integrated values of US joint count for PD signal and rheumatoid factor showed predictive value in relation to progression of radiographic erosion (R = .64). Moreover, time-integrated values of US joint count for PD signal, rheumatoid factor, and erythrocyte sedimentation rate were predictors of progression of the total radiographic score (R = .59), the study showed.
“The persistence of synovial PD signal appears to have predictive value in relation to radiographic progression in patients with RA who are treated with anti-TNF agents,” the study authors concluded.
Translating research into practice
“This technique is routinely available, noninvasive, and is a relatively inexpensive bedside imaging modality with high patient acceptability, which allows the scanning of all peripheral joints as many times as required,” the researchers noted. This is why “we use it routinely,” said Paul Emery, MD, a professor of rheumatology at the University of Leeds in the United Kingdom.
Reference
1. Naredo E, M?kker I, Cruz A, et al. Power Doppler ultrasonographic monitoring of response to antitumor necrosis factor therapy in patients with rheumatoid arthritis. Arthritis Rheum. 2008;58:2248-2256.