Estimating a preference-based index from the Japanese SF-36

Abstract

Objective: The main objective was to estimate a preference-based SF-6D index from the SF-36 for Japan and compare to the UK results.Study design and setting: The SF-6D was translated into Japanese. 249 health states defined by this version of the SF-6D were then valued by a representative sample of 600 members of the Japanese general population using standard gamble. These health state values were modelled using classical parametric random effects methods with individual level data and OLS on mean health state values, together with a new nonparametric approach using Bayesian methods of estimation.Results: All parametric models estimated on Japanese data were found to perform less well than their UK counterparts in terms of poorer goodness of fit, more inconsistencies, larger prediction errors and bias, and evidence of systematic bias in the predictions. Non-parametric models produce a substantial improvement in out of sample predictions. The physical, role and social dimensions have relatively larger decrements than pain and mental health compared to the UK.Conclusion: The differences between Japan and UK valuation of the SF-6D make it important to use the Japanese valuation data set estimated using the non-parametric Bayesian technique presented in this paper. The SF-36 is one of the most widely used generic health survey instruments.[2] There is substantial evidence of the ability of the eight dimension scores of the SF-36 to describe the health differences between patient groups and to track changes over time. However, the methods for scoring the SF-36 are not preference-based and do not provide a means to derive QALYs. The SF-6D was developed as a practical tool for obtaining a preference-based index from SF-36 data. [3] Given the high cost of undertaking valuation surveys, early work using preference-based measures has tended to use the valuation results from just one or two countries, which for the EQ-5D [4] and SF-6D has been the UK and for the HUI [5] has been Canada. However, significant differences have been found between countries, for example values obtained in the UK EQ-5D surveys and those from Japan [6] and USA [7] and between Canadian values for the HUI2 and those obtained in the UK [8]. This paper presents results from undertaking a valuation of the SF-6D in Japan and compares it to results for the UK.An important problem for preference-based measures has been their size and the consequent need to model health state values from valuation of a subset of possible states. Classical modelling with random effects estimated using generalised least squares (GLS) has met with some success, but has encountered major challenges due to the nature of the distribution of

Changes in Health Utility of Patients after Cardiac Surgery

“…The higher the limitation in each domain, the higher the subtraction from the baseline [16,17]. After assessment with the SF-36, SF-36 scores were converted to mean SF-6D utility scores by iHope International (iHope International., Co. Ltd., Kyoto, Japan) based on work in previous studies [10,12,13].…”

“…Each session was composed of a warm-up, aerobic exercise, resistance training, and cool down period. Exercise intensity during aerobic exercise was maintained at anaerobic threshold heart-rate level using treadmill walking or cycle ergometer with a rating of perceived exertion of [11][12][13] (according to the Borg 6-20 scale) [4,5,8].…”

“…The reported goals of cardiac rehabilitation (CR) for these patients are to improve exercise capacity, reduce coronary risk factors, improve health-related quality of life (HRQOL), and reduce subsequent cardiac events, sudden death, all-cause mortality, and hospitalization costs [5][6][7][8][9]. However, with regard to the economic evaluation of hospital costs, several previous studies suggested that health utility, which can be assessed by several preference-based utility measures, is an important measure in the analysis of cost effectiveness in health care [10][11][12][13].…”

“…One such measure, the short-form 6D (SF-6D), which is an instrument providing a summary score based on the SF-36 measure, was developed recently [10][11][12][13]. The reason for developing the SF-6D was to enlarge the bases for economic evaluations while retaining the descriptive richness and sensitivity to change of the SF-36 [10][11][12][13].…”

“…The reason for developing the SF-6D was to enlarge the bases for economic evaluations while retaining the descriptive richness and sensitivity to change of the SF-36 [10][11][12][13].…”