Validation of the Dutch version of the Walking Impairment Questionnaire

ObjectivesThe Walking Impairment Questionnaire (WIQ) is a frequently used questionnaire to evaluate patients with intermittent claudication (IC). The aim of this study is to validate the Dutch WIQ for the European situation using the metric system.DesignValidation study.MaterialsAfter translation and cultural adaptation of the WIQ, 130 patients with IC completed the Dutch WIQ, the RAND-36, and the EuroQol questionnaire. Walking distances were determined by treadmill testing.MethodsCorrelations between the WIQ, the two quality of life questionnaires, and walking distances were calculated to determine validity. Reliability and internal consistency were determined using the intraclass correlation coefficient (ICC) and Cronbach's alpha, respectively.ResultsSignificant correlations were found between the WIQ and the absolute claudication distance (ACD) (0.52), EuroQol (0.33) and seven domains of the RAND-36. Test–retest reliability expressed by the ICC was 0.89. The internal consistency determined by Cronbach's alpha was 0.92 for the total WIQ score. Furthermore, a lower WIQ score corresponds to a shorter ACD.ConclusionsThis study shows that the Dutch version of the WIQ using the European metric system is a valid, reliable and clinically relevant instrument for assessing walking impairment in patients with intermittent claudication.