Session Information
Date: Tuesday, October 23, 2018
Title: Muscle Biology, Myositis and Myopathies Poster III: Treatment and Classification Criteria
Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Patients with 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 both adult/juvenile form of IIM and they are applicable also in patients with amyopathic DM (ADM) and in IBM even without the results of muscle biopsy. The objective of this study was to evaluate the performance of the new classification criteria for IIM in a large retrospective cohort of patients. Methods:
Consecutive patients with a clinical diagnosis of IIM, based on physician opinion, referred to a rheumatology unit from 1995 to 2018 were included and assessed according to the B&P and the EULAR/ACR criteria. Data were collected from an existing database and, when missing, additional variables were retrieved from the patient’s records when available. Cohen’s kappa (K) was used to measure the agreement between physician opinion and the classification criteria; in addition, sensitivity and specificity were calculated. Results:
A total of 424 patients were included in the analysis (M 157, F 269, mean age at the onset 53.5±17.5 years). In 18 patients the onset <18. According to the physician opinion 190 patients had PM, 51 IBM, 146 DM, 11 Juvenile DM (JDM), 4 ADM and 22 incomplete IIM.
Applying the B&P criteria, 406 patients (94.8%) were classifiable as IIM (172 definite, 141 probable, 93 possible): 277 PM (95 def, 106 prob, 76 poss) and 129 DM (77 def, 35 prob, 17 poss). With the EULAR/ACR criteria 351 (82.8%), could be classified as IIM (258 def, 89 prob, 4 poss): 161 PM (83 def, 76 prob, 2 poss), 121 DM (117 def, 4 prob), 44 IBM (41 def, 3 prob, 1 poss), 11 ADM, 13 juvenile IIM (11 DM, 2 PM). The Cohen’s K, the sensitivity and the specificity for the criteria are reported in table 1.
Eighteen patients were not classifiable according to B&P criteria (11 PM, 1 DM, 1 ADM and 3 incomplete IIM) and 73 according to EULAR/ACR criteria (52 PM, 9 DM, 1 ADM, 1 JDM, 10 incomplete IIM). Missing detailed information on patterns of muscle weakness and muscle biopsy features were explanations for not being able to classify most patients. Conclusion:
The new EULAR/ACR criteria performed well in a retrospective cohort using data from a myositis register and patient records from a myositis clinic, but they depend on muscle strength testing of upper and lower extremities as well as of proximal and distal muscles in the legs.
|
Criteria |
Subtype |
Cohen’s K |
Sensitivity |
Specificity |
|
Bohan and Peter |
Overall |
0.108 |
0.97 |
0.16 |
|
PM |
0.479 |
0.97 |
0.38 |
|
|
DM |
0.705 |
0.75 |
0.91 |
|
|
EULAR/ACR |
Overall |
0.142 |
0.84 |
0.45 |
|
PM |
0.492 |
0.72 |
0.84 |
|
|
DM |
0.755 |
0.76 |
0.96 |
|
|
IBM |
0.765 |
0.93 |
0.98 |
To cite this abstract in AMA style:
Barsotti S, Leclair V, Notarnicola A, Ekholm L, Dani L, Dastmalchi M, Lundberg IE. Performance of the New EULAR/Acr Classification Criteria for Idiopathic Inflammatory Myopathies (IIM) in a Large Monocentric IIM Cohort [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/performance-of-the-new-eular-acr-classification-criteria-for-idiopathic-inflammatory-myopathies-iim-in-a-large-monocentric-iim-cohort/. Accessed .« Back to 2018 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/performance-of-the-new-eular-acr-classification-criteria-for-idiopathic-inflammatory-myopathies-iim-in-a-large-monocentric-iim-cohort/