ObjectiveTo develop and validate a patient knowledge questionnaire regarding axial spondyloarthritis (axSpA).MethodsKnowledge considered essential for patients with axSpA was identified through Delphi rounds among rheumatologists, healthcare professionals (HCPs), and patients, then reformulated to develop the knowledge questionnaire. Cross-sectional validation was performed in 14 rheumatology departments to assess internal validity (Kuder-Richardson coefficient), external validity, acceptability, reproducibility (Lin concordance correlation coefficient), and sensitivity to change (knowledge score before vs after patient education sessions and effect size).ResultsThe Spondyloarthritis Knowledge Questionnaire (SPAKE) is a self-administered 42-item questionnaire with a 32-item short form, both scored 0 to 100, assessing knowledge of disease, comorbidities, pharmacological treatments, nonpharmacological treatments, self-care, and adaptive skills. In the validation study (130 patients; 67 [51.5%] male, mean age 43.5 [SD 12.9] yrs), the mean (SD) score of the long-form questionnaire was 71.6 (15.4), with higher scores (better knowledge) in nonpharmacological treatments and adaptive skills and lower scores in cardiovascular comorbidity and pharmacological treatments. Acceptability was good, with no missing data; the internal validity coefficient was 0.85. Reproducibility was good (0.81, 95% CI 0.72-0.89). SPAKE showed good sensitivity to change; scores were 69.2 (15.3) then 82.7 (14.0) after patient education sessions (Hedges effect size = 0.92, 95% CI 0.52-1.31).ConclusionSPAKE is a knowledge questionnaire for patients with axSpA, developed with the involvement of HCPs and patients and reflecting current recommendations for the management of axSpA. SPAKE will be useful in assessing knowledge acquisition and self-management strategies in routine care and research.