Journal Article

ASAS modification of the Berlin algorithm for diagnosing axial spondyloarthritis: results from the SPondyloArthritis Caught Early (SPACE)-cohort and from the Assessment of SpondyloArthritis international Society (ASAS)-cohort

de Hooge, Manouk, Reijnierse, Monique, van den Berg, Rosaline, Sieper, Joachim, Landewé, Robert, van Gaalen, Floris, Rudwaleit, Martin, Huizinga, Tom, van der Heijde, Désirée

2013

Overview

Objective To compare the original Berlin algorithm for diagnosing axial Spondyloarthritis (axSpA) with two modifications in the SPondyloArthritis Caught Early (SPACE)-cohort and the Assessment of SpondyloArthritis international Society (ASAS) axSpA criteria validation (ASAS)-cohort. Methods Patients in the SPACE-cohort (back pain ≥3 months, ≤2 years, onset <45 years) and the ASAS-cohort (undiagnosed chronic back pain) were diagnosed according to three algorithms: original (inflammatory back pain (IBP) mandatory), modification 1 (IBP defined by ≥3/5 IBP-features instead of ≥4/5) and modification 2 (IBP deleted as obligatory entry criterion, added as SpA-feature). Diagnosis by rheumatologist, ASAS axSpA criteria and likelihood ratio product were used as external standards to test the performance of the algorithms. Results SPACE-cohort: Compared to the diagnosis by rheumatologist (either axSpA or no-axSpA), the original algorithm agreed in 120 patients (76.4%). Agreement decreased using modification 1 (119 patients; 75.8%), increased using modification 2 (125 patients; 79.6%). Sensitivity increased from 66.2% (original) to 72.3% (modification 1) and 78.5% (modification 2). Specificity decreased more using modification 1 (83.7% to 78.3%) than when using modification 2 (83.7% to 79.6%). ASAS-cohort: Compared to the diagnosis by rheumatologist (either axSpA or no-axSpA), the original algorithm agreed in 484 patients (70.7%). Agreement increased using modification 1 (520 patients; 75.9%) and modification 2 (548 patients; 80.0%). Sensitivity increased from 65.3% (original) to 77.9% (modification 1) and 79.6% (modification 2). Specificity decreased more using modification 1 (79.2% to 72.2%) than when using modification 2 (79.2% to 75.6%). Conclusions ASAS accepted a modified algorithm for diagnosing axSpA in which IBP is excluded as obligatory entry criterion and added as SpA-feature.

• Publisher: BMJ Publishing Group Ltd and European League Against Rheumatism,Elsevier Limited
• Subject: Adult / Algorithms / Ankylosing Spondylitis / Back pain / Back Pain - etiology / Chronic Pain - etiology / Cohort Studies / Decision Support Techniques / Decision Trees / Diagnostic Errors / Female / HLA-B27 Antigen - blood / Humans / Laboratories / Magnetic Resonance Imaging / Male / Middle Aged / Patients / Sensitivity and Specificity / Society / Spondylarthritis - complications / Spondylarthritis - diagnosis / Spondyloarthritis / Young Adult