Cost-effectiveness analysis of X-ray- and MRI-based diagnostic pathways in axial spondyloarthritis
Bogdan Kostyrko, Dominik Marvin Deppe, Denis Poddubnyy, Torsten DiekhoffBackground
Diagnostic imaging plays a central role in the diagnosis of axial spondyloarthritis (axSpA). Current guidelines recommend a stepwise imaging approach, starting with X-ray and, in negative cases, following with magnetic resonance imaging (MRI), are increasingly questioned.
Objectives
The aim of this study is to compare the clinical effectiveness and economic impact of different imaging-based diagnostic strategies for axSpA.
Design
A decision-analytic model was developed to evaluate three diagnostic scenarios: (A) initial X-ray screening followed by MRI if negative, (B) a stricter X-ray-based strategy with higher diagnostic thresholds followed by MRI, and (C) direct MRI.
Methods
A hypothetical cohort of 100000 patients with suspected axSpA and a disease prevalence of 30% was modeled. Different input parameters (prevalence, therapy duration with biologic or targeted disease modifying antirheumatic drugs (b/tsDMARD) before clinical reassessment, and proportion of patients undergoing therapy escalation with b/tsDMARD) were varied across three scenarios. Cost-effectiveness was expressed as costs per correctly diagnosed axSpA case. Parameter uncertainty was addressed using probabilistic sensitivity analysis with 5000 Monte Carlo simulations and threshold analyses.
Results
Unit costs were estimated at 166.91€ for single MRI and 10994.48€ for b/tsDMARD therapy for 11 months. The scenario comparison yielded different break-even values: with MRI costs below 2256€ and b/tsDMARD therapy costs above 682€, scenario C was associated with lower cost. In probabilistic sensitivity analyses, scenario C was economically favorable in 100% of simulations. When varying different input parameters across alternative combinations, these directional trends remained consistent. To support transferability to other health-care systems, we calculated an
Conclusion
MRI-based diagnostic pathway represents a clinically and economically balanced alternative to X-ray-based axSpA diagnostics and may be adapted to different healthcare systems.