Use of generic and condition-specific measures of health-related quality of life in NICE decision-making: a systematic review, statistical modelling and survey

摘要

Background: The National Institute for Health and Care Excellence recommends the use of genericudpreference-based measures (GPBMs) of health for its Health Technology Assessments (HTAs). However,udthese data may not be available or appropriate for all health conditions.udObjectives: To determine whether GPBMs are appropriate for some key conditions and to exploreudalternative methods of utility estimation when data from GPBMs are unavailable or inappropriate.udDesign: The project was conducted in three stages: (1) A systematic review of the psychometric propertiesudof three commonly used GPBMs [EQ-5D, SF-6D and Health Utilities Index Mark 3 (HUI3)] in four broadlyuddefined conditions: visual impairment, hearing impairment, cancer and skin conditions. (2) Potentialudmodelling approaches to ‘map’ EQ-5D values from condition-specific and clinical measures of healthud[European Organisation for Research and Treatment of Cancer Quality-of-life Questionnaire Core 30ud(EORTC QLQ-C30) and Functional Assessment of Cancer Therapy – General Scale (FACT-G)] are comparedudfor predictive ability and goodness of fit using two separate data sets. (3) Three potential extensions to theudEQ-5D are developed as ‘bolt-on’ items relating to hearing, tiredness and vision. They are valued using theudtime trade-off method. A second valuation study is conducted to fully value the EQ-5D with and withoutudthe vision bolt-on item in an additional sample of 300 people.udSetting: The valuation surveys were conducted using face-to-face interviews in the respondents’ homes.udParticipants: Two representative samples of the UK general population from Yorkshire (n = 600).udInterventions: None.udMain outcome measures: Comparisons of EQ-5D, SF-6D and HUI3 in four conditions with variousudgeneric and condition-specific measures. Mapping functions were estimated between EORTC QLQ-C30udand FACT-G with EQ-5D. Three bolt-ons to the EQ-5D were developed: EQ + hearing/vision/tiredness.udA full valuation study was conducted for the EQ + vision.udResults: (1) EQ-5D was valid and responsive for skin conditions and most cancers; in vision, itsudperformance varied according to aetiology; and performance was poor for hearing impairments. The HUI3udperformed well for hearing and vision disorders. It also performed well in cancers although evidence wasudlimited and there was no evidence in skin conditions. There were limited data for SF-6D in all fourudconditions and limited evidence on reliability of all instruments. (2) Mapping algorithms were estimated toudpredict EQ-5D values from alternative cancer-specific measures of health. Response mapping using all theuddomain scores was the best performing model for the EORTC QLQ-C30. In an exploratory analysis, audlimited dependent variable mixture model performed better than an equivalent linear model. In the fulludanalysis for the FACT-G, linear regression using ordinary least squares gave the best predictions followedudby the tobit model. (3) The exploratory valuation study found that bolt-on items for vision, hearing andudtiredness had a significant impact on values of the health states, but the direction and magnitude ofuddifferences depended on the severity of the health state. The vision bolt-on item had a statisticallyudsignificant impact on EQ-5D health state values and a full valuation model was estimated.udConclusions: EQ-5D performs well in studies of cancer and skin conditions. Mapping techniquesudprovide a solution to predict EQ-5D values where EQ-5D has not been administered. For conditionsudwhere EQ-5D was found to be inappropriate, including some vision disorders and for hearing, bolt-onsudprovide a promising solution. More primary research into the psychometric properties of the genericudpreference-based measures is required, particularly in cancer and for the assessment of reliability.udFurther research is needed for the development and valuation of bolt-ons to EQ-5D.udFunding: This project was funded by the UK Medical Research Council (MRC) as part of the MRC-NIHRudmethodology research programme (reference G0901486) and will be published in full in Health TechnologyudAssessment; Vol. 18, No. 9. See the NIHR Journals Library website for further project information.