Internal Consistency and Validity of the Spanish Version of the Quality of Life Questionnaire Specific for Obstructive Sleep Apnea: Sleep Apnea Quality of Life Index

a b s t r a c t Introduction: The objective of the present study was to validate the Spanish version of the SAQLI, which is a health-related quality of life (HRQL) questionnaire specific for sleep apnea-hypopnea syndrome (SAHS), and to assess its sensitivity to change. Material and methods: A multicenter study performed in a group of patients with SAHS (apnea-hypopnea index (AHI) ≥5) who had been referred to the centers' Sleep Units. All patients completed the fol- lowing questionnaires: SF-36, FOSQ, SAQLI and Epworth scale. The psychometric properties (internal consistency, construct validity, concurrent validity, predictive value, repeatability and responsiveness to change) of the SAQLI were assessed (four domains: daily function, social interactions, emotional function and symptoms; an optional fifth domain is treatment-related symptoms). Results: One hundred sixty-two patients were included for study (mean age: 58±12; Epworth: 10±4; BMI: 33±5.9 kg m−2; AHI: 37±15 h−1). The factorial analysis showed a construct of four factors with sim- ilar distribution to the original questionnaire domains. Internal consistency (Cronbach's alpha between 0.78 and 0.82 for the different domains), concurrent validity for SF-36, Epworth scale and FOSQ, and test-retest reliability were appropriate. The predictive validity of the questionnaire showed no signifi- cant correlations with the severity of SAHS. SAQLI showed good sensitivity to change in all the domains of the questionnaire (P<.01). Conclusions: The Spanish version of the SAQLI is a valid HRQL measurement with appropriate psycho- metric properties for use in patients with SAHS and it is sensitive to change.