Translation and Validation of the Danish Version of the Zurich Claudication Questionnaire

STUDY DESIGN: Validation study. OBJECTIVES: To translate and validate the Zurich Claudication Questionnaire (ZCQ) into a Danish version of the disease-specific patient-reported outcome measure (PROM) for patients with lumbar spinal stenosis (LSS), which assesses symptom severity, physical function, and satisfaction after surgery. METHOD: Translation into a Danish version of the original questionnaire by back- and forward-translating the questionnaire and finally transforming a prefinal test version into a final and cross-cultural adapted version. Validation was performed as a cohort study assessing floor-ceiling effects, internal consistency, test-retest reproducibility, criterion validity, discriminant validity, and responsiveness to change. RESULTS: Fifty-three patients were consecutively included in the study, 53 healthy controls were matched. Floor effect was seen in the postoperative data. Internal consistency, Cronbach’s alpha was good to excellent. Substantial test-retest reproducibility was found using Cohen’s weighted kappa. The Danish ZCQ showed moderate to strong association with similar domains of Oswestry Disability Index, Short Form 36, Euro QoL 5D, visual analogue scale–leg and back. The questionnaire showed significant responsiveness to change and a significant discriminant validity between LSS patients and healthy controls. CONCLUSION: This study shows the Danish translation of the original ZCQ to be well understood by Danish patients. The Danish version is furthermore a reliable and valid questionnaire, which is responsive to change.