Reasons for diagnostic delays of axial spondyloarthritis

Introduction: The probability of development of axial spondyloarthritis (axSpA) is estimated to be above 90% among patients with chronic back pain, presence of HLA B27 antigen and positive family history of ankylosing spondylitis (AS), psoriasis, reactive arthritis, inflammatory bowel disease or uveitis. The nonradiographic axSpA and ankylosing spondylitis diseases' activity has a comparable impact on the patients' quality of life and from the practical point of view the approach to treatment of each of them is the same. The aim: The attempt to identify the reasons of diagnostic delays of AS among patients hospitalized in the Rheumatology and Connective Tissue Diseases Department in Lublin and to suggest the ways of improving the accuracy of diagnostic track among other healthcare providers than rheumatologists.

Material and methods: We performed a retrospective analysis of the records of 82 patients' with the established diagnosis of AS, hospitalized in the Rheumatology and Connective Tissue Diseases Department in Lublin in 2000-2019, and of 45 years of age and older.

Results: From among 82 patients (28 women and 54 men) the diagnosis of AS after 45 years of age was established in 25 patients (10 women and 15 men) - group t, and in the other 57 patients (group n) the diagnosis was established before 45 years of age. On average the age at the time of diagnosis in the whole group (t+n) was 40,7±10,2 (18-76) years, the age at the beginning of inflammatory back pain (age of axial symptoms) was 30,9±8,5 (13-51) years and the diagnostic delay (period between first axial symptoms and diagnosis establishment) was 9,75±9,5 (0-46) years. We did not find any statistically significant associations between sex and age at the moment of diagnosis, age of the beginning of axial symptoms and the time of diagnostic delay. There was no significant difference of incidence of enthesitis, uveitis, arthritis, prevalence of family history of spondyloarthritis and CRP level between group t and n. Antigen HLA B27 was more frequently present in group t.

Conclusions: Instead of the recognition progress and worldwide popularization of knowledge about axSpA, the diagnostic delays in this field are still estimated to last many years, the patients are looking for other specialists' help, and they can be not knowledgeable of the inflammatory back pain criteria. Currently, HLA B27 antigen and C-reactive protein are the two most commonly used biomarkers for diagnostic and disease activity monitoring purposes of axSpA and magnetic resonance is the only "imaging biomarker". The presence of extra-axial symptoms does not improve the diagnostic sensitivity.