Diagnostic delay in axial spondyloarthritis: a systematic review and meta-analysis

Abstract Background. Delay to diagnosis in axial spondyloarthritis (axSpA) is longer than many other rheumatic diseases. Prolonged delay has been shown to associate with poorer outcomes including functional impairment and quality of life. Our aims were to describe 1) global variation in delay to diagnosis, 2) factors associated with delay, and 3) differences in diagnostic delay between axSpA and psoriatic arthritis (PsA).Methods. We searched Medline, PubMed, EMBASE and Web of Science using a predefined protocol in accordance with PRISMA guidelines. Delay to diagnosis was defined as years between age at symptom onset and age at diagnosis. We pooled mean diagnostic delay using random-effects inverse variance meta-analysis. We examined variations in pooled estimates using pre-specified subgroup analyses and sources of heterogeneity using meta-regression.Results. A total of 64 studies reported mean diagnostic delay in axSpA patients. The pooled mean delay was 6.7 years (95% confidence interval 6.2 to 7.2) with high levels of heterogeneity. Delay to diagnosis did not improve over time when stratifying results by year of publication. Studies from high-income countries (defined by the World Bank) reported longer delay than those from middle-income countries. Factors consistently reported to be associated with longer delay were: lower education levels, younger age at symptom onset and absence of extra-articular manifestations. Pooled estimate for diagnostic delay from 8 PsA studies was significantly shorter, at 2.6 years (95%CI 1.6 to 3.6). Conclusion. For axSpA patients, delay to diagnosis remains unacceptably prolonged in many parts of the world, although some countries have reported remarkable improvements. Patient factors (education) and disease presentation (age at onset and extra-articular manifestations) should inform awareness campaigns to improve delay. Targets for improvement should aim to resemble delays in other spondyloarthritis patients.