What is the economic burden of delayed axial spondyloarthritis diagnosis in the UK?

Objective The objective of this study was to develop an economic model to determine the annual cost of delayed axial SpA diagnosis in the UK, adopting both National Health Service (NHS) and societal perspectives.Methods We developed a Markov economic model to estimate the costs of delayed axial SpA diagnosis in the UK. Model parameters were sourced from a 2016 National Axial Spondyloarthritis Society patient survey, anonymized patient-level data, the published literature, and expert opinion. A literature-defined, mixed cohort (64% male) of people assumed to have axial SpA, whose age at symptom onset was 26 years, were targeted. To assess the robustness of the results, base case and probabilistic sensitivity analyses were performed.Results In a simulated cohort of 1000 patients, with a mean time to diagnosis of 8.5 years, we estimate the cumulative costs of delayed diagnosis per person living with axial SpA to be 193 pound 512 (95% CI: 108 770-306 789). The costs were led by productivity losses (65.1%) and out-of-pocket expenses (31.3%). The total annual cost resulting from delayed axial SpA diagnosis in the UK has been estimated at 3.1 pound billion and 12.5 pound billion, based on a prevalence of 0.3% (Assessment of SpondyloArthritis international Society classification criteria) and 1.2% (European Spondyloarthropathy Study Group classification criteria), respectively.Conclusion Delayed axial SpA diagnosis carries high costs for society due to productivity losses. Early diagnosis and treatment could offer significant benefits to the patient and potentially reduce productivity losses; however, future research is needed to evaluate the long-term health economic impact.