The effect of individually assessed preference weights on the relationshipbetween holistic utilities and nonpreference-based assessment

In the assessment of health-related quality of life, nonpreference-based me thods usually show only moderate correlations with utility-based measures. One cause may be that patients assign different weights to the various doma ins of health-related quality of life, for which nonpreference-based method s usually do not allow. Utilities reflect a weighted sum of these domains. The aim of this study is to assess whether the relationship between utility -based methods and nonpreference-based measures improves through the use of individual importance weights for the various domains of health-related qu ality of life. For this purpose, weights were obtained from 41 early-stage breast cancer patients, both before and during treatment, for seven pre-sel ected health status attributes representing important domains of health-rel ated quality of life during chemotherapy. The importance weights were combi ned with the level of functioning on the attributes. These scores were regr essed against patients' utilities for their actually experienced health sta te during chemotherapy, measured by means of a visual analog scale (VAS), a time trade-off (TTO), and a standard gamble (SG). Before weighting, the se ven attribute scores were more strongly related to TTO and SG utilities tha n the nonpreference-based questionnaires. However, when they were combined with the importance weights, only the correlation with the SG utilities imp roved, and only so with the importance weights obtained before chemotherapy . In this study, assigning individually assessed preference weights to self -reported level of functioning did not result in stronger relationships wit h utilities.