Objective: Our aim was to validate Spanish and Catalan versions of the Liver Disease Quality of Life questionnaire (LDQOL) for use in liver transplant patients.
Methods: The LDQOL consists of the SF-36 generic measure of health-related quality of life (HRQOL) and 12 disease-specific dimensions for liver disease patients. The Spanish and Catalan versions of the questionnaire were administered to 138 patients with a liver transplant. Cronbach's alpha coefficients (CAC) were used to test the internal consistency of disease-specific scales. Test-retest reliability was calculated using the Intraclass Correlation Coefficient (ICC) in a sub-group of 41 patients who completed the questionnaire on two occasions 1 to 2 weeks apart. Validity was analysed by determining the instrument's capacity to discriminate between patient groups classified according to years since transplant, disease etiology, and symptom severity. Ceiling and floor effects were also calculated.
Results: Internal consistency in the disease-specific dimensions was acceptable or good (CACs 0.60-0.97), as was test-retest reliability in all dimensions (statistically significant CCIs of 0.62-0.89), except the symptoms dimension (CCI=0.46, P<.05). Few differences were found in disease-specific dimension scores between patients classified according to number of years since transplant or etiology, but differences were found in some dimensions according to symptom severity. Moderate to severe ceiling effects were found in several disease-specific dimensions.
Conclusions: The Spanish and Catalan versions of the LDQOL may be useful for measuring HRQOL in this population, though it will be important to investigate further the instrument's sensitivity to change.