ObjectiveEpionics SPINE (ES), a novel device that measures spinal movements using electronic sensors including range of motion (RoM) and speed (range of kinematics [RoK]), has already been validated in patients with mechanical back pain and healthy individuals. This study aimed to evaluate ES for quantification of spinal mobility in patients with axial spondyloarthritis (axSpA).MethodsA total of 153 individuals, 39 female and 114 male, were examined including 134 patients with axSpA, of whom 40 had nonradiographic (nr)-axSpA, 94 had radiographic (r)-axSpA; 19 were healthy controls (HCs). The results were compared using mean ES scores and modeling was performed using multivariable logistic regression models resulting in good validity and high discriminative power.ResultsES measurements showed meaningful differences between patients with axSpA and HCs (all P < 0.001), as well as between r- and nr-axSpA (P < 0.01). In patients with axSpA, a negative correlation between ES and Bath Ankylosing Spondylitis Metrology Index values was found: –0.76 ≤ r ≤ –0.52 (P < 0.05). Bath Ankylosing Spondylitis Functional Index scores showed a similar trend (r > –0.39). Patients with r-axSpA had a more limited and slower spinal mobility than those with nr-axSpA. Other patient-reported outcomes almost did not correlate.ConclusionThis study shows that the ES is an objective performance measure and a valid tool to assess spinal mobility in axSpA, also based on the Outcomes Measures in Rheumatology (OMERACT) criteria. RoK and RoM scores provide additional information on physical function of patients with axSpA.