Session Type: Poster Session (Sunday)
Session Time: 9:00AM-11:00AM
Background/Purpose: Patients with Idiopathic Inflammatory Myopathies (IIM) have been classified mainly according to Bohan and Peter (B&P) criteria, proposed in 1975. In 2017 the new EULAR/ACR criteria were proposed. They are able to classify patients with IIM and they are applicable even without results of a muscle biopsy.
The objective of this study was to evaluate the performance of the new EULAR-ACR myositis classification criteria in a large retrospective cohort of IIM patients from Argentina.
We applied the EULAR-ACR criteria in an external real-world cohort of consecutive IM cases from the Argentinean Rheumatology Society Myositis study group. Consecutive patients with IM based on physician diagnosis were included in the database. Data were collected form a preexisting database.
Methods: B&P criteria and EULAR-ACR were applied to each patient. For the purpose of this study we applied the non-biopsy EULAR/ACR criteria to non-dermatomyositis (DM) patients without biopsy (in the original paper those criteria only applied to DM patients). And we also applied the non-biopsy criteria to patients with a biopsy to be able to evaluate whether IM diagnosis might have been done without a biopsy.
We compared the performance of EULAR-ACR criteria with physician diagnosis and with B&P criteria.
Results: A cohort of 132 patients with physician diagnosis of IM were included in the study.
Seventy-seven percent were females, mean age at IM diagnosis was 45 (SD 17) years. Ninety- four (71%) without muscle biopsy and 37 (29%) with biopsy.
Table 1 shows the performance of all criteria in our cohort. EULAR-ACR criteria were considered positive if patient fulfilled probable or definitive criteria.
Figure 1 shows the performance of EULAR/ACR criteria (with and without biopsy) in patients who underwent muscle biopsy (37 patients)
Table 2 shows sensitivity of EULAR/ACR criteria according to the physician diagnosis as gold standard.
When we analyzed the sensitivity of EULAR-ACR (criteria without biopsy) according to B&P criteria as gold standard, the sensitivity was 86% (73.2-94.9). We were not able to evaluate the sensitivity of EULAR/ACR criteria with biopsy according to B&P criteria because all patients with biopsy fulfilled this criteria.
Conclusion: The sensitivity of EULAR-ACR criteria according to physician diagnosis in our cohort was lower than previous reports for both probable and definitive cut-off points. Sensitivity of EULAR-ACR criteria performed better using B&P criteria as gold standard. If criteria without biopsy are applied to patients with biopsy most of them fulfill criteria. Only in 6 patients of 37 the biopsy would change diagnosis.
To cite this abstract in AMA style:Virasoro B, Gomez R, Capelusnik D, Braillard Poccard A, Schneeberger E, Papasidero S, Viola M, de la Vega M, Costi C, Garcia M, Asnal C, Cappuccio A, Yucra D, Tamborenea N, Rivero M, Granel A, Vergel Orduz L, Dalpiaz M, Bande J, Segura Escobar C, Pisoni C. Performance of the European League Against Rheumatism/American College of Rheumatology Idiopathic Inflammatory Myopathies Classification Criteria in a Myositis Cohort from Argentina [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/performance-of-the-european-league-against-rheumatism-american-college-of-rheumatology-idiopathic-inflammatory-myopathies-classification-criteria-in-a-myositis-cohort-from-argentina/. Accessed May 29, 2020.
« Back to 2019 ACR/ARP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/performance-of-the-european-league-against-rheumatism-american-college-of-rheumatology-idiopathic-inflammatory-myopathies-classification-criteria-in-a-myositis-cohort-from-argentina/