Quality of life in patients with kidney stones: translation and validation of the Spanish Wisconsin Stone Quality of Life Questionnaire.

Abstract

The Spanish version of the Wisconsin Stone Quality of Life (WISQOL) questionnaire was developed and validated. A double-back translation of the WISQOL was conducted and syntactic amendments were made, resulting in the Spanish version of the WISQOL (S-WISQOL) which then went through a readability analysis. Stone formers from two hospitals in Mexico (Merida and Monterrey) filled in the S-WISQOL and the Short Form 36 (SF36). Convergent validity was assessed by the correlation of both questionnaires. Internal consistency was evaluated by Cronbach's α, and external validity by comparing between centers. The impact of clinical settings on patients' health-related quality of life (HRQOL) scores was tested. Each hospital's institutional review board approved the project and informed consent was obtained from all participants. A total of 87 Spanish-speakers patients completed the S-WISQOL and SF36 and a good correlation was found between both (r = 0.75, p < 0.001). S-WISQOL readability was rated as "easy". Patients from Merida had longer median duration (years) with stones, more stone-related procedures, and hospitalizations, and scored lower on WISQOL (p = 0.006). Internal consistency was good as Cronbach's α coefficients ranged between acceptable and excellent. Stone-related admissions and duration of stones were inversely correlated with S-WISQOL score (-0.254 and -0.283, respectively; p < 0.005) but not to SF36. The S-WISQOL is an internally consistent, reliable, and valid instrument to assess HRQOL in Spanish-speaking patients with kidney stones. The S-WISQOL is generalizable as demonstrated by good external validity among centers. S-WISQOL scores can be added as an outcome for kidney stone treatments.