AB0697 PERFORMANCE OF DIFFERENT CRITERIA SETS FOR INFLAMMATORY BACK PAIN IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS IN DEMOCRATIC REPUBLIC OF CONGO

Abstract

Background:Inflammatory back pain (IBP) is the most prominent clinical feature for an early diagnosis of axial spondyloarthritis. The performance of the criteria sets for IBP has not yet been assessed in clinical practice in the Democratic Republic of Congo (DRC).Objectives:To assess and to compare the performance of different IBP criteria sets in axial spondyloarthritis (SpA) outpatients attending the rheumatology unit of the University Hospital of Kinshasa, DRC.Methods:One hundred and eight Congolese outpatients with axial SpA defined by rheumatologist’s clinical judgment were included in the spondyloarthritis cohort of the University Hospital of Kinshasa from March 1st2015 to February 28, 2017. Calin criteria, Berlin criteria and ASAS criteria sets for IBP were performed to assess their performance against clinical judgment. Detailed history, clinical examination and imaging of sacroiliac joints by plain radiography were obtained. Sacroiliac joint radiographic lesions were scored with the modified New York criteria. Magnetic resonance imaging and HLA B27 were not performed. Fifty additional patients with a diagnosis of chronic (>3 months) mechanical low back pain (MLBP) were included as control group. The performance of each item and different criterias was evaluated using sensitivity, specificity, and likelihood ratio (LR). Baseline characteristics of the mechanical and inflammatory back pain cohorts were compared with chi-square or Student t tests as appropriate.Results:The mean age was 43.8±15.1 years in SpA patients versus 62.4±9.1 years in controls (MLBP patients) with respective sex ratio (M/F) of 1/0.8 and 1/2.1. There were significantly more male patients in the ankylosing spondylitis (AS) group than in the non-radiographic axial spondyloarthritis group (p<0.01). Among the criteria sets, Calin criteria showed the best sensitivity (92.6%) while the Berlin criteria showed the best specificity (97.6%) in the detection of IBP patients. The new ASAS criteria for IBP compared to the two previous criteria sets did not show good sensitivity nor specificity (sensivity 80%, specificity 62%, LR+ 1.05 (0.90 – 1.22), LR- 0.52 (0.39 – 0.69), 95%CI).Conclusion:The Calin criteria set would be useful for epidemiological and clinical studies in DRC. The ASAS criteria set for IBP is not better than other criteria sets in the screening of IBP for Congolese patients with axSpA.