Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: The ASAS classification criteria have provided new insights in the classification of axial SpA. Some studies suggested different characteristics between the imaging and clinical arms of axial SpA particularly in response to biologics. However, available data is still limited and additional information is required. We present our results in a large group of patients with non-radiographic axSpA (nr-axSpA).
Methods: Patients were recruited from two centers with dedicated programs in SpA. Among the registries of these institutes patients coded as nr-axSpA were identified. Two rheumatologist from each center re-scored the X-rays and excluded those with diagnostic changes of AS. SIJ MRI readings were done according to ASAS recommendations. Clinical and laboratory characteristics were then obtained for each group from the clinical database. Patients were stratified into imaging and clinical arms based on the clinical, imaging and laboratory findings. The imaging arm was further stratified into B27- and B27+ groups.
Results: There were a total of 200 nr-axSpA patients in the combined cohorts. The mean age and disease durations were 38±11.1 and 9.1±8.1 years respectively. 44.5% were male and 59% were HLA-B27-positive. There were 147 (73.5%) and 53 (26.5%) patients in the MRI-positive and clinical arms respectively. 28.6% of the patients have been treated with biologics. Comparison of imaging vs clinical arms of nr-axSpA demonstrated that age, sex, disease duration, BASDAI, BASFI and BASMI indices were similar between the groups. Uveitis and psoriasis were significantly increased in the clinical arm group. In contrast, increased acute phase reactants and good response to NSAIDs were more prevalent in the imaging arm. Other variables such non-response to biologics were distributed evenly between the groups (Table-1). We compared B27+ vs B27- imaging patients and clinical arm patients (all B27+ by definition). Age, sex distribution and disease durations were similar between these three groups. Increased acute phase reactants and good response to NSAIDs were higher in the both imaging groups compared to clinical arm patients. Biological utilization rates, family history and presence of uveitis were higher in all B27+ patients regardless of whether they were in the clinical or imaging arm. The remainder of the extra-articular features, BASDAI, BASFI and BASMI levels and non-response to biologics were comparable between the three subsets (Table 1).
Conclusion: In this large cohort of nr-axSpA patients the clinical characteristics of nr-axSpA patients classified by the imaging vs clinical arms were comparable. It was of note that there was a comparable TNFi failure due to lack of response in both groups despite the higher CRP in the imaging arm. Our findings provide real world clinical support for the validity of the clinical arm for the classification of nr-axSpA.
|Clinical arm (n=53)||Imaging arm (n=147)||p|
|Sex, Male, %||47.2||43.5||0.74|
|Disease duration, years||10.7±9.4||8.6±7.6||0.18|
|Mean follow-up (months)||46.1±48.1||31.2±30.7||0.04|
|Increased acute phase response, %||18.2||36.5||0.03|
|Good response to NSAIDs, %||50||70.2||0.03|
|Biologic ever, %||41.5||24||0.02|
|Switch ever, %||40.9||44.1||0.81|
|Switch due to LOE, %||80||83.3||0.9|
|BASDAI50 response, %||33.3||41.2||0.78|
|Family history, %||30.8||26.9||0.59|
Clinical Arm (n=53)
|B27 pos (n=65)||B27 neg (n=82)|
|Sex, Male, %||47.2||49.2||39||0.42|
|Disease duration, years||10.7±9.4||8.9±7.4||8.4±7.8||0.31|
|Mean follow-up (months)||46.1±48.1||35±31.2||28.3±30.2||0.02|
|Increased acute phase response, %||18.2||40||33.8||0.05|
|Good response to NSAIDs, %||50||69.1||71||0.07|
|Biologic ever, %||41.5||33.8||16||0.003|
|Switch ever, %||40.9||57.1||23.1||0.14|
|Switch due to LOE, %||80||78.6||100||0.6|
|BASDAI50 response, %||33.3||38.1||46.2||0.77|
|Family history, %||30.8||38.1||18.3||0.03|
To cite this abstract in AMA style:Sari I, Haroon N, Can G, Akin B, Omar A, Kenar G, Yarkan H, Onen F, Inman RD, Akkoc N. Comparability of Patients Classified As Non-Radiographic Axial Spondyloarthritis By the Imaging Vs Clinical Arms of the ASAS Criteria [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/comparability-of-patients-classified-as-non-radiographic-axial-spondyloarthritis-by-the-imaging-vs-clinical-arms-of-the-asas-criteria/. Accessed October 25, 2020.
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