Validation of the Italian version of Wisconsin Stone Quality Of Life (WISQOL). A prospective Italian Multicentric Study

Abstract

PURPOSE Urolithiasis is a worldwide spread condition that affect patients’ Health Related Quality of Life (HRQOL), which measurement is an important tool for routinary clinical and research practice. Disease-specific HRQOL measures demonstrated to perform better in assessing effects of specific conditions. A disease-specific questionnaire for kidney stones, the WISQOL, has been validated in different language, but an Italian version is still missing. Our aim is to produce and validate the Italian version of WISQOL (IT-WISQOL). METHODS Patients undergoing any elective treatment for upper urinary tract stones were enrolled. A multi-step process with forward- and back-translation was used to translate WISQOL to Italian. Patients were evaluated within 15 days pre-operatively and then at 1-,3-months post-operatively and administered both IT-WISQOL and SF-36v2. Post-operative data such as 30 days post-operative complications, late stone-related events, stone free status, stone complexity were collected. Cronbach’s αwas used to evaluate internal consistency of IT-WISQOL, while Spearman’s rho was used for item and inter-domain correlations and IT-WISQOL with SF-36v2 correlation. RESULTS We found excellent internal consistency across all domains (α ≥ 0.88), particularly when the total score is considered (α = 0.960). Test–retest reliability showed excellent results for the total questionnaire (Pearson correlation value: 0.85). the Inter-domain association ranged from 0.497 to 0.786. Convergent validity was con­firmed by a good correlation with subdomains of the SF-36v2 measures. CONCLUSION IT-WISQOL is a reliable tool to measure HRQOL in stone patients. It shows analogue characteristics if compared to English WISQOL.