MADRID, SPAIN — Individuals with certain arthritis risk factors, including musculoskeletal pain and anti-citrullinated protein antibodies (ACPA), are more likely than healthy controls to present with joint erosion in ultrasound scans, according to the results of a study presented at the 2019 European Congress of Rheumatology, held June 12-15, 2019, in Madrid, Spain.

The study included 82 participants with ACPA and musculoskeletal pain who had not been diagnosed with arthritis at baseline and 100 age-matched healthy blood donors as the controls. Researchers performed baseline ultrasound scans to assess joint erosion, inflammatory activity, and gray scale synovial hypertrophy in 36 small joints. Follow-up time was 68 (23-91) months. Researchers used a ProFocus system set at 0.8 kHz pulse repetition frequency to grade power Doppler.

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In the initial 3 years of the study, they blinded all participants and treating physicians to ultrasound and power Doppler results and performed clinical examinations in follow-up to track the development of arthritis. Researchers used Cox regression analysis to investigate the associations between arthritis development and baseline ultrasound results (adjusted for age), symptom duration, smoking habits, rate of erythrocyte sedimentation, sex, rheumatoid factor, ACPA levels, and C-reactive protein levels.

Synovial hypertrophy was significantly more common in metacarpophalangeal joints in the participant group compared with controls ((5.2% vs 2.5%, respectively; P <.001). The same was true for proximal interphalangeal joints 2-5 (6.6% vs 1.5%, respectively; P <.001); however, metatarsophalangeal joints 1-5 were more likely to be scored gray scale >0 in controls compared with the participants (49% vs 24%, respectively; P <.001).

The participants showed significantly more positive power Doppler than did the controls (P <.05). Researchers detected erosions on ultrasound in 16% (n = 13) of participants and none of the controls (P <.001). Arthritis developed in 48% (n = 39) of the participants after a median of 25 weeks, which was significantly more likely among participants with ultrasound erosions detected at baseline (10/13; 77%) compared with participants without (29/69; 42%; P =.032).

After adjusting for potential confounders using Cox regression, this finding remained significant, with a hazard ratio of 4.2 (95% CI, 1.7-10.4; P =.002). Just 4 of the 13 ultrasound-detected erosions were visible on conventional radiographs.

The study researchers concluded that “[arthritis]-related [ultrasound] findings are more common among patients at increased risk of [rheumatoid arthritis] compared to healthy controls, but with site-specific differences. Erosions detected on [ultrasound] predicted arthritis development. Thus, [ultrasound] assessment of erosions improves risk-stratification of ACPA-positive patients without swollen joints, and potentially identifies patients eligible for very early pharmacotherapy.”

Several of the study authors reported financial associations with pharmaceutical companies. Please visit the reference for a full list of disclosures.

Reference

Ziegelasch M, Eloff E, Berner Hammer H, et al. Joint erosions visible on ultrasound predict arthritis development in patients with ACPA and musculoskeletal pain but no swollen joints. Poster presentation at: Annual European Congress of Rheumatology; June 12-15, 2019; Madrid, Spain. Abstract OP0116.