Validation and cross-cultural adaptation of the Korean version of the Zurich claudication questionnaire in patients with lumbar spinal stenosis

Abstract

Study Design. Linguistic and psychometric validation of a translated questionnaire. Objective. To validate the Korean version of Zurich claudication questionnaire (ZCQ) both linguistically and psychometrically. Summary of Background Data. The ZCQ is considered as a disease specific and gold standard measure for evaluation of patients with lumbar spinal stenosis (LSS). However, there has been no validated Korean version of the ZCQ. Methods. The ZCQ was translated forward and backward, culturally adapted by 2 independent translators, and approved by an expert committee. The final version of the Korean ZCQ was added to a routine questionnaire including a visual analog pain scale (VAS) for back and leg pain, the Oswestry Disability Index (ODI), and the European Quality of Life-5 dimensions (EQ-5D). Psychometric validation included reliability by internal consistency using Cronbach's alpha, the test-retest reliability using intraclass correlation coefficient (ICC), and concurrent validity by comparing the Korean ZCQ to VAS for back/leg pain, ODI, and EQ-5D using Pearson correlation. Results. A total of 109 patients were included in this study. The test-retest intraclass correlation coefficient (ICC) of the ZCQ was shown to have good reliability for all three domains: the ICCs for symptom, function, and satisfaction domains were 0.79, 0.84, and 0.91, respectively. Internal consistency of the Korean ZCQ for the symptom, function, and satisfaction domains was also excellent (Cronbach a = 0.894, 0.939, and 0.961, respectively). For concurrent validity, all three domains of the Korean ZCQ were significantly correlated with external criteria including VAS for back/leg pain, ODI, and EQ-5D. In the assessment of responsiveness, 21 patients who completed the ZCQ both before and after surgery demonstrated significantly different scores for symptom and disability domains. Conclusion. The validated Korean version of the ZCQ is a transculturally equivalent, reliable, and valid tool for use in assessing symptoms, function, and satisfaction with treatment in patients with LSS.