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

Abstract Background Delay to diagnosis in axial SpA (axSpA) is longer than in many other rheumatic diseases. Prolonged delay is associate with poorer outcomes, including functional impairment and quality of life. Our aims were to describe global variation in delay to diagnosis, factors associated with delay, and delay compared with PsA. Methods We searched MEDLINE, PubMed, Embase and Web of Science using a predefined protocol. Diagnostic delay was defined as years between the age at symptom onset and at diagnosis. We pooled the mean delay using random effects inverse variance meta-analysis. We examined variations in pooled estimates using prespecified subgroup analyses and sources of heterogeneity using meta-regression. Results A total of 64 studies reported the mean diagnostic delay in axSpA patients. The pooled mean delay was 6.7 years (95% CI 6.2, 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 delays than those from middle-income countries. Factors consistently reported to be associated with longer delays were lower education levels, younger age at symptom onset and absence of extra-articular manifestations (EAMs). The pooled estimate for diagnostic delay from 8 PsA studies was significantly shorter, at 2.6 years (95% CI 1.6, 3.6). Conclusion For axSpA patients, delay to diagnosis remains unacceptably prolonged in many parts of the world. Patient factors (e.g. education) and disease presentation (onset age and EAMs) should inform campaigns to improve delay.