Formulation of a Mapping Formula to Estimate Well-Being Utility from Clinical Subjective Well-Being Scales.

Abstract

Cost-effective analysis is one of the most useful analyses for political decision-making in medicine under a limited budget. Although the data of the ICEpop CAPability measure for Adults (ICECAP-A) is sometimes essential for the measurement of cost effectiveness, such data are often lacking in most clinical trials. Therefore, a conversion formula (ie mapping) derived from the values of clinical assessment scales into utility is required. We used an internet survey where 500 general residents were asked to fill in four kinds of self-reported questionnaires [ICECAP-A, the Satisfaction with Life Scale (SWLS), Flourishing Scale (FS), and the Scale of Positive and Negative Experience (SPANE)]. A beta regression was conducted with the utility assessed by ICECAP-A as a dependent variable. We developed several mapping formulae depending on available questionnaires. These mapping formulae were well-validated in our validation sample. The models using a greater number of questionnaires tended to show better mapping. The mapping function of our formula was within the range of other reported mapping studies. We believe this formula is useful for cost effective analyses of several trials where utility data are lacking.