[Adaptation and validation of the Spanish version of a disease-specific quality of life measure in patients with systemic lupus erythematosus: the Lupus quality of life]

Background and objective: Systemic Lupus Erythematosus (SLE) is an auto-immune disease that seriously affects quality of life. There are various specific instruments that measure health-related quality of life (HRQOL), but none of them has been adapted to Spanish. We intended to adapt and validate in a Spanish population a specific HRQOL measure in patients with SLE.

Patients and methods: The adaptation was carried out using the translation and back-translation method of the English version of the LupusQoL, with its subsequent application to 115 adults with SLE.

Results: The factorial analysis identified 5 domains of the LupusQoL; the reliability tests showed a high Cronbach alpha coefficient of 0.977 and a high Guttman two-halves coefficient of 0.936; the significant correlations of the LupusQoL with the SF-36 showed a high convergent validity of the questionnaire; in addition, the correlations with the SLEDAI and SLICC were low, which showed its discriminated validity.

Conclusion: The Spanish version of the LupusQoL has stable psychometric properties to measure HRQOL in people with SLE in clinical and research settings in a Spanish-speaking population.