title: Mapping of incontinence quality of life (I-QOL) scores to assessment of quality of life 8D (AQoL-8D) utilities in patients with idiopathic overactive bladder.
abstract: BACKGROUND
  The Incontinence Quality of Life (I-QOL) questionnaire is a commonly used and validated incontinence specific QOL instrument. The objective of this study is to develop an algorithm to map I-QOL to the Assessment of Quality of Life (AQoL) 8D utility instrument in patients with idiopathic overactive bladder (iOAB).
  
  
  METHODS
  I-QOL and AQoL-8D scores were collected in a survey of 177 Australian adults with urinary incontinence due to iOAB. Three statistical methods were used for estimation, namely ordinary least squares (OLS) regression, the robust MM-estimator, and the generalised linear models (GLM). Each included a range of explanatory variables. Model performance was assessed using key goodness-of-fit measures in the validation dataset.
  
  
  RESULTS
  The I-QOL total score and AQoL-8D utility scores were positively correlated (r = 0.50, p < 0.0001). Similarly, the three sub-scales of the I-QOL were correlated with the eight dimensions and two super-dimensions of the AQoL-8D. The GLM estimator, with I-QOL total score as the explanatory variable exhibited the best precision (MAE = 0.15 and RMSE = 0.18) with a mapping function given by AQoL-8D = exp(-1.28666 + 1.011072*I-QOL/100).
  
  
  CONCLUSIONS
  The mapping algorithm developed in this study allows the derivation of AQoL-8D utilities from I-QOL scores. The algorithm allows the calculation of preference-based QOL scores for use in cost-utility analyses to assess the impact of interventions in urinary incontinence.
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Tan
authors.forename: Kwong
authors.initials: K
authors.lastname: Ng
authors.forename: Angelo
authors.initials: A
authors.lastname: Iezzi
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Richardson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001315:Australia; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D053201:Urinary Bladder, Overactive / Q000523:psychology*; D014549:Urinary Incontinence / Q000523:psychology*