Validation of AQoL-8D: a health-related quality of life questionnaire for adult patients referred for otolaryngology

PURPOSE: The purpose of the study was to validate the AQoL-8D questionnaire in the adult population of patients referred to an otolaryngology clinic. METHODS: AQoL-8D was translated into Polish. 463 patients (age18–80 years) with otolaryngological conditions were assessed with the AQoL-8D, SF-6D, and SWLS questionnaires. We investigated the item content-relevance, factor structure by means of Confirmatory Factor Analysis, corrected item-total correlations, Cronbach’s alpha, Pearson correlation of the AQoL-8D scores with results from SF-6D and from the SWLS questionnaires. Finally, ANOVA was used to test the AQoL-8D ability to group the HRQoL of patients in terms of their otolaryngological management type. RESULTS: The median score of item content-relevance was 5.0 for all AQoL-8D items. Confirmatory Factor Analysis revealed the following fit indices: Comparative Fit Index = 0.81; Tucker–Lewis Index = 0.80; and Root Mean Square Error of Approximation = 0.07. Cronbach's alpha for AQoL-8D dimensions ranged from 0.48 to 0.79. Mean item-total correlations over all dimensions, super dimensions, and the instrument overall were higher than 0.3. There was a significant Pearson correlation between the results obtained with AQoL-8D and SF-6D (r = 0.68), and with AQoL-8D and SWLS (r = 0.43). A one-way ANOVA showed a significant effect of management type on HRQoL as measured by AQoL-8D [F(4,458) = 6.12, p < 0.001] CONCLUSION: AQoL-8D provides valid and reliable measures of HRQoL in patients undergoing otolaryngological treatment. Because it is a generic questionnaire, it is possible to make general comparisons of otolaryngology outcomes with those from other subspecialties.