Dados do Trabalho

Título

Quebec Sleep Questionnaire: Reliability of the Brazilian Version of a Specific Quality-of-life Instrument for Obstructive Sleep Apnea

Introdução

Obstructive Sleep Apnea (OSA) is a highly prevalent disease and is associated with significant impact on patient’s quality of life (QOL). As such, reliable and valid instruments for the assessment of QOL in OSA are necessary. The Quebec Sleep Questionnaire ― QSQ ― is the only instrument adapted to Brazilian Portuguese for the measurement of QOL in OSA patients.

Objetivo

To scrutinize the reliability properties of the Brazilian version of the QSQ ― specific health-related quality of life instrument for OSA.

Métodos

This is a cross-sectional study that included 125 OSA patients (AHI ≥ 5) in whom QOL was measured by using the Brazilian version of the QSQ. Reliability was assessed by item-to-total correlation (the correlation of the item to the domain summated score) and by internal consistency with Cronbach’s alpha. Finally, a sub-sample (n=26) was used for the analysis of test-retest stability.

Resultados

The item-to-total analysis demonstrated good correlation between all the items and the scores of their related domains. Item 25 "loud snoring" and the domain "nocturnal symptoms" demonstrated the lowest correlation (Pearson’s r 0.53; p < 0.001) whilst "daily symptoms" domain and the item 17 "feeling decreased energy" presented the highest correlation (Pearson’s r = 0.89; p < 0.001). Global internal consistency was excellent (Cronbach’s alpha 0.95) and internal consistency within each domain ranged from 0.67 for "social interaction" to 0.93 from "diurnal symptoms". Test-retest intraclass correlation coefficients for each domain were: daytime sleepiness, ICC = 0.86; diurnal symptoms, ICC= 0.86; nocturnal symptoms, ICC=0.81; social interactions, ICC=0.74; and emotions, ICC=0.55.

Conclusões

The research provided evidence for the reliability of the Brazilian Version of the QSQ. Additional studies will be needed in order to assess the validity of the instrument.

Palavras-chave

Obstructive sleep apnea, quality of life, questionnaires.