Clin. Rheumatol. 2014 Sep;33(9):1255-62.

EVALUATION OF A NEW EROSION SCORE BY MUSCULOSKELETAL ULTRASOUND IN PATIENTS WITH RHEUMATOID ARTHRITIS: Is US ready for a new erosion score?

 

*Ohrndorf S, *Messerschmidt J, Reiche BE, Burmester GR, Backhaus M. *equal contribution

Department of Rheumatology and Clinical Immunology, Charité – Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.

 

Abstract

Objective: To evaluate a new semi-quantitative (0-5) musculoskeletal ultrasound (US) erosion score in patients with rheumatoid arthritis (RA) and to prove its usefulness in the detection of disease activity, and success of therapy.

Patients and methods: Thirty-eight patients with RA (mean disease duration 10.1± 11.9 yrs) were enrolled. Start or change of therapy (DMARD/biologics) was an inclusion criterion. DAS28, laboratory (ESR, CRP) and US data were evaluated before new therapy initiation and after 1, 3, 6, and 12 months. Thirteen joints of the clinically more affected hand and forefoot (wrist and MCP, PIP, MTP joints 2-5) were analyzed for synovitis in greyscale (GS) and power Doppler (PD) US, tenosynovitis/paratenonitis in GS/PDUS (wrist, MCP-level), and for erosions. Erosions were analyzed by a new semi-quantitative score (grade 0 = no erosion, grade 1: < 1 mm, grade 2: 1 – < 2 mm, grade 3: 2 – < 3 mm, grade 4: > 3 mm, grade 5: multiple bone erosions).

Results: After 12 months, DAS28 decreased from 4.5 to 3.4 (p<0.001), the synovitis score in GSUS from 26.3 to 12.8 (p=0.001), and the synovitis score in PDUS from 10.6 to 4.1 (p<0.001). The erosion score decreased from 21.5 to 18.1 (p=0.046). There were longitudinal significant correlations between the new erosion score and both the DAS28 (r=0.368; p=0.025) and the synovitis score in PDUS (r=0.365; p=0.026) over a 1-year follow-up period. 

Conclusion: The new erosion score might be a useful tool for the evaluation of erosive changes by US in RA patients. In the course of DMARD and biologic therapy, it was responsive under 1-year follow-up examination.

PMID: 24824913

 

Supplement:

Rheumatoid arthritis (RA) is a chronic inflammatory disease which can lead to severe joint destruction and disability. Early diagnosis of RA is important and decisive for the further progress of the disease. In addition to the collection of clinical and laboratory data, sensitive imaging techniques are essential for the assessment of the disease activity. By musculoskeletal ultrasound (US) it is possible to detect the early inflammatory soft tissue and bone destructive process. Its excellent soft tissue contrast allows a good differentiation between exsudative and proliferative synovial changes by greyscale US (GSUS). The power Doppler US (PDUS) allows further assessment of inflammatory joint activity by the distinction between active and inactive pannus tissue. Furthermore, the detection of erosive lesions by US has a great diagnostic relevance and plays an important role in the early diagnosis of RA. Erosions by US in patients with RA are defined as a discontinuity of the bone surface which is visible in two perpendicular planes [1]. They can be presented very well, if the lesions are accessible by the ultrasonic probe. Preferred joints for the detection of erosions by US are particularly MCP II, MCP V and MTP V in the medial/lateral plane. These can be specifically investigated by US in an early disease when no radiological erosion is observed. Furthermore, a good differentiation between erosions and bony apposition is quite possible [2]. An international accepted erosion score does not exist until now. In favor of objective and successful documentation, standardized comparison and valuable course assessment, grading of erosions by US is very meaningful. Therefore, the aim of the present study was the evaluation of a new semi-quantitative erosion score (0-5) by US in order to prove its usefulness in the detection of disease activity and success of therapy in patients with RA. The erosion score was defined as follows: grade 0: no erosion, grade 1: < 1 mm, grade 2: 1 – 2 mm, grade 3: 2 – 3 mm, grade 4: > 3 mm, grade 5: multiple lesions > 3 mm, i.e. more than one erosion in the examined joint region [3]. For better standardization and reproducibility, the measurement of the erosion size was only done in the longitudinal plane (long to the axis of the examined area). The semi-quantitative erosion score was validated before under the aspect of ‘construct validation’ by a study of Finzel et al. [3], in which the erosion score had been compared to the erosion assessment by micro-CT and was found to be useful for the evaluation and grading of erosions in US.

Thirty-eight patients with the confirmed diagnosis of RA (based on ACR/EULAR criteria 2010 [4]) were enrolled in this study and analyzed within one year at time 0 (before (change of) treatment with DMARD/biologic agents) and after 1, 3, 6, and 12 months. All US scans were performed in accordance with the guidelines of EULAR [5]. At each visit, nine joints of the clinically more affected (for tenderness and/or swelling) hand (wrist, MCP and PIP joints II to V) and four joints of the clinically more affected forefoot (MTP II to V) were scanned in all planes (dorsal, palmar/plantar, radial/lateral in MCP II, V and MTP V) for synovitis in GSUS and PDUS, tenosynovitis/paratenonitis (GSUS and PDUS) and erosions. For the analysis of synovitis we used the semi-quantitative (0-3) synovitis score for GSUS according to Scheel et al. [6], and the synovitis score for PDUS (0-3) published by Szkudlarek et al. [7] according to the OMERACT definitions [1]. These resulted in 30 joint regions for the synovitis score in GS and PDUS, for 14 joint regions for the tenosynovitis/paratenonitis score in GS and PDUS, and for 33 joint regions for the erosion score. Erosions in each of the joint regions were analyzed by using the new semi-quantitative erosion score (see above) and also on a qualitative basis (0/1).

 

 

Table 1: Activity parameters in the 1-year-follow-up (total cohort, n=38)

tab1

 

The results of the study for the total cohort (n=38 pts.) were as follows: After 12 months of therapy, DAS28 decreased to 3.4 (∆ -1.1; p<0.01), the synovitis score in GSUS to 12.8 (∆ -8.7; p=0.01), the synovitis score in PDUS to 4.1 (∆ -6.4; p<0.01), the tenosynovitis score in GSUS to 0.7 (∆ – 1.7; p=0.002), and the tenosynovitis score in PDUS to 0.5 (∆ -1.6; p=0.007). The erosion score decreased to 18.1 (∆ -3.4; p=0.046), while the number of erosions decreased to 6.9 (Table 1). Comparison of changes in both treatment groups (DMARDs vs. biologics) showed the following results: In the conventional DMARD group, the DAS28 was initially 4.3; the synovitis score in GSUS 22.4, the synovitis score in PDUS 8.6, and the erosions score 12.0. After 12 months, the DAS28 decreased to 3.2 (∆ -1.1; p=0.036), the synovitis score in GSUS to 9.8 (∆ -12.7; p=0.004), the synovitis score in PDUS to 3.0 (∆ -5.6; p=0.008) and the erosion score degraded slightly to 10.9 (∆ -1.1; p=0.132) (Table 2). The biologic group showed greater changes; in this cohort, the DAS28 decreased from initially 4.8 to 3.5 (∆ -1.3; p<0.001), the synovitis score in GSUS from 29.9 to 15.5 (∆ -14.4; p<0.001), the synovitis score in PDUS from 12.3 to 5.2 (∆ -7.2; p<0.001) and the erosion score numerically decreased from 30.1 to 24.7 (∆ -5.4; p=0.055) (Table 3). An example is given by Figure 1.

 

Table 2: Activity parameters in the 1-year-follow-up (DMARD cohort, n=18)

tab2

 

Table 3: Activity parameters in the 1-year-follow-up (biologic cohort, n=20)

tab3

 

In summary, the results of the study presented the new erosion score to be useful and, furthermore, responsive under different antirheumatic therapies. Furthermore, a significant reduction of the erosion score was detected in the total patient group (p=0.046). In the detailed analysis, neither in the patient group under biologic therapy nor in that being on conventional DMARD therapy, the erosion scores significantly decreased. However, on patient-level, “healing effects” of erosive lesions were detected in 20 patients (52.6%), at least, of whom twelve (31.5%) were on biologic and eight (21.1%) on DMARD therapies. A reduction of both the number and the magnitude of erosions were seen. Therefore, a possible diminution of erosions is a new result in the follow-up use of US in patients with RA, especially after initiation of new biologic regimes. To our knowledge, this is the first analysis, which detected and classified bone healing phenomena with an erosion score by musculoskeletal US.

 

fig4

Figure 1: 46 years old seropositive RA patient,
RA since 01/2001.
Tocilizumab (biologic group) since 07/2009.

Ultrasound examination at baseline.
MTP V, dorsal view:
Synovitis score in GSUS grade 2.
Synovitis score in PDUS grade 1.
MTP V lateral view: erosion score grade 4 (5.5 mm).

Ultrasound examination after 12 months.   
MTP V dorsal view:
Synovitis score in GSUS grade 0.
Synovitis score in PDUS grade 0.
MTP V lateral view: erosion score grade 2 (2.0 mm).

 

In conclusion, the new semi-quantitative erosion score is a useful tool for the evaluation of erosive changes by ultrasound in patients with RA. Furthermore, it showed responsiveness in the 1-year follow-up by a significant correlation to PDUS during one year. Besides, it has potential to present possible erosive healing (see above).Therefore, the new erosion score can reflect both disease activity and therapeutic success in the course of new therapies.

 

References

  1. Wakefield RJ, Balint PV, Szkudlarek M, et al. Musculoskeletal US including definitions for ultrasonographic pathology. J Rheumatol 2005;32:2485-2487.
  1. Backhaus M, Kamradt T, Sandrock D, et al. Arthritis of the finger joints: a comprehensive approach comparing conventional radiography, scintigraphy, ultrasound, and contrast-enhanced magnetic resonance imaging. Arthritis Rheum. 1999;42:1232-1245.
  2. Finzel S, Ohrndorf S, Englbrecht M, et al. A detailed comparative study of high-resolution US and micro-computed tomography for detection of arthritic bone erosions. Arthritis Rheum 2011;63:1231-1236.
  3. Aletaha D, Neogi T, Silman AJ, et al. 2010 Rheumatoid Arthritis Classification Criteria. An American College of Rheumatology/European League Against Rheumatism Collaborative Initiative. Ann Rheum Dis 2010;69:1580-1588.
  4. Backhaus M, Burmester GR, Gerber T, et al. Guidelines for musculoskeletal US in rheumatology. Ann Rheum Dis 2001;60:641-649.
  5. Scheel AK, Hermann KG, Kahler E, et al. A novel ultrasonographic synovitis scoring system suitable for analyzing finger joint inflammation in rheumatoid arthritis. Arthritis Rheum. 2005;52:733-743.
  6. Szkudlarek M, Court-Payen M, Jacobsen S et al. Interobserver agreement in ultrasonography of the finger and toe joints in rheumatoid arthritis. Arthritis Rheum. 2003;48:955-962.

 

Acknowledgements:  This study was supported by Chugai Pharma Marketing Frankfurt, Germany. Chugai did not exert any influence on the statistical analysis or preparation of the manuscript.

 

Contact: Marina Backhaus, MD, Professor of Rheumatology

fig2Sarah Ohrndorf, MD

Department of Rheumatology and Clinical Immunology

Charité-Universitätsmedizin Berlin

Charitéplatz 1, D-10117 Berlin, Germany

marina.backhaus@charite.de 

fig3sarah.ohrndorf@charite.de

 

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