Doppler Signal and Bone Erosions at the Enthesis Are Independently Associated With Ultrasound Joint Erosive Damage in Psoriatic Arthritis

Abstract

Objective To explore the association of the OMERACT ultrasound (US) entheseal abnormalities with the presence of US joint bone erosions in psoriatic arthritis (PsA). Methods Consecutive PsA patients were included in this cross-sectional study. Demographic and clinical parameters were collected. A bilateral US assessment was carried out at the following entheses: plantar fascia, quadriceps, patellar (proximal and distal) and Achilles tendons. The following US entheseal abnormalities were registered: hypoechogenicity, thickening, Doppler signal <2mm from the bony cortex, calcification/enthesophyte, bone erosion. The presence of US joint bone erosions was investigated at the 2nd and 5th metacarpophalangeal (MCP) joints, ulnar head and 5th metatarsophalangeal (MTP) joint, bilaterally, as well as at the level of the most inflamed joint on physical examination. Multiple linear regression analysis was performed to identify clinical and/or US variables associated with US-detected joint bone erosions. Results A total of 104 PsA patients were enrolled. At least one joint bone erosion was found in 47/104 patients (45.2%). Bone erosions were most frequently detected at 5th MTP joint level (42/208 joints, 20.2 %; 32/104 patients, 30.8%). In the multivariate model, only PD signal at the enthesis (P<0.001, standardized β=0.51), bone erosions at the enthesis (P=0.02, standardized β=0.2), PsA disease duration (P=0.04, standardized β=0.17) and greyscale joint synovitis (P=0.03, standardized β=0.42) were associated with US-detected joint bone erosions. Conclusion PD signal and bone erosions at the enthesis represent sonographic biomarkers of a more severe subset of PsA in terms of US-detected joint erosive damage.

New Advances in the Knowledge of Elemental Enthesis Lesions: Doppler, Erosion, and Thickness

“…The results of Smerilli et al 12 are also consistent with the results obtained by other authors, who point out that the enthesis PD is the main US lesion for enthesis evaluation in SpA and PsA, 14 even suggesting that it is sufficient to define enthesitis not only as an isolated elemental lesion. 15 In their cohort of patients with PsA, Smerilli et al 12 found PD present in 55.8% of patients and 10.6% of entheses, similar to previous findings (66.7% of patients and 10.2% of entheses), 16 although a proper comparison seems complex due to the different selection of explored entheses and disease activity states of the included patients. Another series also reported high percentages of enthesis PD (81.5-96%), [16][17][18] and Mease et al 19 proposed that the enthesis domain could be associated with greater PsA disease activity, globally supporting the association between the enthesis domain (highlighted by PD) and the systemic activity in SpA and PsA, thereby emphasizing the importance of introducing new methods to improve the evaluation of entheses.…”

“…In this study, 12 joint erosions were found to be associated in the univariate and multi-variate model and in the logistic regression analysis with enthesis PD (β 0.51, P < 0.001 and odds ratio [OR] 1.74, 95% CI 1.17-2.59, P < 0.01), enthesis erosion (β 0.20, P = 0.02 and OR 3.17, 95% CI 1.30-7.77, P = 0.01), and greyscale joint synovitis (β 0.42, P = 0.03 and OR 2.59, 95% CI 1.16-5.78, P = 0.02). The results of Smerilli et al 12 are also consistent with the results obtained by other authors, who point out that the enthesis PD is the main US lesion for enthesis evaluation in SpA and PsA, 14 even suggesting that it is sufficient to define enthesitis not only as an isolated elemental lesion. 15 In their cohort of patients with PsA, Smerilli et al 12 found PD present in 55.8% of patients and 10.6% of entheses, similar to previous findings (66.7% of patients and 10.2% of entheses), 16 although a proper comparison seems complex due to the different selection of explored entheses and disease activity states of the included patients.…”

“…21 El Miedany et al 22 also evaluated potential structural joint damage predictors in an early PsA cohort and reported peripheral and sacroiliac X-ray damage after 1 year, demonstrating an increased probability for structural progression related to PD at entheses using the GUESS. To our knowledge, Smerilli et al 12 is the first study to evaluate structural damage in terms of peripheral erosions by US, and not by X-ray, and its association with the presence of enthesitis; however, the results led to the same conclusions. Erosion appears in this study as the other elementary lesion of the enthesis related to joint damage in the multivariable analysis, which is very interesting since the evidence in this field is scarce but in agreement with previous studies.…”

“…The results shown by Smerilli et al 12 demonstrated how entheses thickening was related to structural joint damage in the univariate analysis but not in the multivariate analysis, such that the thickening is also relevant in the association of the enthesis with other disease domains. The problem is that in the aforementioned OMERACT reliability exercise, 5 thickening achieved the worst results, with a κ of 0.1 (95% CI 0-0.7), and this needs to be improved, highlighting the importance of the article by Keenan et al published in this issue.…”

“…In this issue of The Journal of Rheumatology, 2 new studies help deepen the knowledge and relevance of entheses in SpA and PsA. 12,13 Smerilli et al 12 share the results of a joint and entheses US study performed in 104 patients with PsA, exploring the association between enthesis involvement and peripheral joint damage measured by US joint erosions, demonstrating how enthesis US findings have become a biological marker of surrogate structural joint damage in PsA and reinforcing the central role of enthesis inflammation in PsA and its association with other outcomes and domains in this disease (joints, in this case). In this study, 12 joint erosions were found to be associated in the univariate and multi-variate model and in the logistic regression analysis with enthesis PD (β 0.51, P < 0.001 and odds ratio [OR] 1.74, 95% CI 1.17-2.59, P < 0.01), enthesis erosion (β 0.20, P = 0.02 and OR 3.17, 95% CI 1.30-7.77, P = 0.01), and greyscale joint synovitis (β 0.42, P = 0.03 and OR 2.59, 95% CI 1.16-5.78, P = 0.02).…”