Validation of the Dutch version of the VascuQol questionnaire and the Amsterdam linear disability score in patients with intermittent claudication

Purpose To assess the reliability and validity of the Dutch version of the vascular quality of life questionnaire (VascuQol) and the AMC Linear Disability Score (ALDS) in patients with stable intermittent claudication (IC). Methods During a 5-month period we performed a prospective study in which we included every patient with stable IC, who visited our vascular surgery outpatient clinic and consented to participate. Forty consecutive patients filled in the Dutch VascuQol, the ALDS, and Short Form-36 (SF-36). Twenty patients filled in the same questionnaires after 4 weeks. Internal reliability consistencies were expressed as Cronbach's alpha. Test-retest reliability was expressed as intraclass correlation coefficients (ICC). Construct validity was expressed as Spearman rho correlations between SF-36 and relevant domains of Dutch VascuQol and the ALDS. Results Internal reliability consistencies were, respectively, good and excellent for the total scores of VascuQol, SF-36, and ALDS (Cronbach's alpha. 0.87, 0.89, and 0.92). Test-retest reliability was excellent for the total VascuQol scores [ICC 0.91 (95% CI, 0.78-0.96)], and for the ALDS [ICC 0.90 (95% CI, 0.76-0.96)]. Spearman correlations between VascuQol, ALDS, and SF-36 domains varied from r = 0.34-0.79. Conclusion The Dutch VascuQol is a valid and reliable questionnaire for assessment of Qol in patients with IC. This study confirms the good clinimetric properties of the ALDS for assessing disability in patients with IC.