Validation of the Turkish version of the Wisconsin stone-quality of life questionnaire.

Abstract

We validated the Turkish version of the Wisconsin Stone-Quality of Life (WISQoL) questionnaire for male and female patients with kidney stones. The Turkish version of the WISQoL questionnaire was developed following a well-established multistep process. A total of 84 patients with kidney stones completed the Turkish WISQoL questionnaire, including the other validated questionnaires as The Short Form Health Survey (SF-36 v2) and Beck's Depression Inventory. Patients completed questionnaires before percutaneous nephrolithotomy (PNL) surgery as well as 2-4 weeks after surgery. Reliability was evaluated by internal consistency (tested by Cronbach's alfa) and test-retest reliability between week 2 and 4 (tested by Spearman correlation). Domain structures were examined by interdomain correlations using Spearman correlation coefficient. Convergent validity was assessed by correlating the scores of general health domain to the SF-36 v2, and the scores of emotional impact domain to the Beck's Depression Inventory questionnaire. Sensitivity to change was assessed by comparing scores before and after PNL surgery with the Wilcoxon signed rank test. Discriminant validity was evaluated by comparing the results of patients 2 and 4 weeks after surgery with Wilcoxon-rank sum tests. The Turkish version of the WISQoL demonstrates good internal consistency (Cronbach's α=0.72-0.78) and test-retest reliability (p>0.05). Inter-domain associations within the WISQOL showed a substantial correlation between various WISQoL domains, indicating a high conceptual relationship between the domains. Also, the Turkish version of the WISQoL showed convergent validity with the corresponding validated questionnaires (Spearman's rho correlation coefficient=0.44-0.78). All domains of the WISQoL showed significant sensitivity to change (p≤0.001). The Turkish version of the WISQoL is a generally reliable instrument that can be self-administered by Turkish patients with kidney stones in clinical and research settings. Further clinical studies in Turkish settings would be useful to provide powerful data on sensitivity to change.