title: Mapping Between the Sydney Asthma Quality of Life Questionnaire (AQLQ-S) and Five Multi-Attribute Utility Instruments (MAUIs).
abstract: Economic evaluation of health services commonly requires information regarding health-state utilities. Sometimes this information is not available but non-utility measures of quality of life may have been collected from which the required utilities can be estimated. This paper examines the possibility of mapping a non-utility-based outcome, the Sydney Asthma Quality of Life Questionnaire (AQLQ-S), onto five multi-attribute utility instruments: Assessment of Quality of Life 8 Dimensions (AQoL-8D), EuroQoL 5 Dimensions 5-Level (EQ-5D-5L), Health Utilities Index Mark 3 (HUI3), 15 Dimensions (15D), and the Short-Form 6 Dimensions (SF-6D).
  
  
  
  Data for 856 individuals with asthma were obtained from a large Multi-Instrument Comparison (MIC) survey. Four statistical techniques were employed to estimate utilities from the AQLQ-S. The predictive accuracy of 180 regression models was assessed using six criteria: mean absolute error (MAE), root mean squared error (RMSE), correlation, distribution of predicted utilities, distribution of residuals, and proportion of predictions with absolute errors <0.0.5. Validation of initial 'primary' models was carried out on a random sample of the MIC data.
  
  
  
  Best results were obtained with non-linear models that included a quadratic term for the AQLQ-S score along with demographic variables. The four statistical techniques predicted models that performed differently when assessed by the six criteria; however, the best results, for both the estimation and validation samples, were obtained using a generalised linear model (GLM estimator).
  
  
  
  It is possible to predict valid utilities from the AQLQ-S using regression methods. We recommend GLM models for this exercise.
authors: Flinders Health Economics Group, Flinders University, A Block, Repatriation General Hospital, 202-16 Daws Road, Daw Park, Adelaide, SA, 5041, Australia. billingsley.kaambwa@flinders.edu.au.
authors: Billingsley
authors: B
authors: Kaambwa
authors: Centre for Health Economics, Building 75, 15 Innovation Walk, Monash University, Clayton, VIC, 3800, Australia.
authors: Gang
authors: G
authors: Chen
authors: Flinders Health Economics Group, Flinders University, A Block, Repatriation General Hospital, 202-16 Daws Road, Daw Park, Adelaide, SA, 5041, Australia.
authors: Julie
authors: J
authors: Ratcliffe
authors: Centre for Health Economics, Building 75, 15 Innovation Walk, Monash University, Clayton, VIC, 3800, Australia.
authors: Angelo
authors: A
authors: Iezzi
authors: Centre for Health Economics, Building 75, 15 Innovation Walk, Monash University, Clayton, VIC, 3800, Australia.
authors: Aimee
authors: A
authors: Maxwell
authors: Centre for Health Economics, Building 75, 15 Innovation Walk, Monash University, Clayton, VIC, 3800, Australia.
authors: Jeff
authors: J
authors: Richardson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000503:physiopathology*; D005260:Female; D006304:Health Status; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D011788:Quality of Life; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D055815:Young Adult