Validity of the Spanish version of the Chronic Liver Disease Questionnaire (CLDQ) as a standard outcome for quality of life assessment

The Chronic Liver Disease Questionnaire (CLDQ) measures the impact on quality of life of chronic liver diseases, regardless of underlying etiology. The aim of this study was to develop a Spanish version of the CLDQ, and to assess its acceptability, reliability, validity, and sensitivity to change. The forward and back-translation method by bilingual translators, with expert panel and pilot testing on patients, was used for the adaptation. The final version was self-administered, together with the Short Form-36 Health Survey (SF-36), on 149 consecutive patients with chronic liver disease. Child-Turcotte-Pugh scores were evaluated by a physician. To assess reproducibility and responsiveness the CLDQ was readministered to a subsample of stable patients and to those who had received a liver transplant. Validity was evaluated via exploratory factor analysis, the CLDQ pattern across severity groups, and correlation coefficients with "itching" and SF-36 scores. Cronbach's alpha and Intraclass Correlation Coefficient for CLDQ global score were 0.93 and 0.90, respectively, demonstrating good reliability. Validity was supported by correlations of the CLDQ with SF-36 and "itching," and CLDQ severity gradient (global score means were 5.5, 5.2, 5.0, and 4.5 in patients with no cirrhosis, cirrhosis Child-Turcotte-Pugh A, B, and C, respectively; P = 0.012). Responsiveness was shown by a high CLDQ improvement in patients who had received liver transplant (mean change = -1.4; P < 0.001). In conclusion, the Spanish CLDQ is reliable, valid, responsive, and equivalent to the original. These findings support its use as a standard outcome for patients with chronic liver diseases within the whole severity range, from "no cirrhosis" to transplant recipients, both in Spanish and international studies.