Do established health-related quality-of-life measures adequately capture the impact of chronic conditions on subjective well-being?

Abstract

Objectives

The paper explores how two well-established, utility-based health-related quality-of-life (HRQoL) measures (EQ-5D and 15D) capture the negative effects of various chronic conditions on subjective well-being (SWB). This is important, as both SWB and health utility can be important aims of health policy and instruments in resource allocation.

Methods

A general population survey representing the Finnish population aged 30 years and over covering 25 self-reported somatic conditions and four psychiatric disorders diagnosed by interviews.

Results

Both EQ-5D and 15D fail to capture the effects of some chronic conditions on SWB, but the conditions differ between the instruments. Even after controlling for both EQ-5D and 15D simultaneously, common psychiatric disorders decrease SWB by 0.4 points on a scale 1–10.

Conclusions

Using health utility as a basis for resource allocation is likely to underfund the treatment of psychiatric disorders, in comparison to their effect on the SWB of the population. Different HRQoL instruments yield somewhat different results for different conditions.

Introduction

Health is an integral component of the quality of life. Health-related quality of life (HRQoL) is an increasingly important outcome measure in health care, as the ethos of health care has gradually changed from the paternalistic reduction of illness to improving the subjective well-being of autonomous individuals. Another reason has been the epidemiological transition of the burden of disease from high-mortality diseases, such as infections, to various chronic conditions. Third, the optimal allocation of health care resources is a crucial issue in all industrialized countries, because a rapidly aging population and new technologies increase both possibilities and costs. HRQoL holds great promise for health economics [1]. The debate as to which outcome measure should be used in the allocation of resources is, however, far from over, for both theoretical and practical reasons [2].

Preference-based, generic health-related quality-of-life (HRQoL) measures, such as EQ-5D, SF-6D, HUI, AQoL and 15D, enable numeric valuation of different health states as a single summary score. This is commonly referred to as health utility, and reflects the subjective preferences of individuals for various health states [1]. Utility scores are also the quality-component of quality-adjusted life years (QALYs) which enable direct comparison of different diseases and treatments. QALYs have become important in health economics and health policy decision-making [3], but the differences in methodology have resulted in greatly varying estimates for specific conditions [4].

However, the ultimate goal for human existence, in many streams of ancient and modern culture, is not health or functional capacity as such but to make people “happy” or “satisfied” with their lives [5]. In psychology and economics, the pursuit of determining what makes people happy or satisfied with their lives has been done by means of quantitative research using representative data sets with answers to questions on subjective well-being (SWB) [6], [7], [8], [9], [10], [11].

It is evident that HRQoL measures and SWB focus, at least partly, on different aspects of well-being. HRQoL measures stress the state of health and functional capacity strongly, while SWB puts more weight on the personal feeling of well-being. Thus, SWB captures also non-health aspects of individual well-being. Hence, its main promise is that it is a broader measure of individual well-being than HRQoL. The potential discrepancy between HRQoL and SWB measures is particularly topical, because the prominent economists and social scientists have advocated recently that the advanced societies should put much more emphasis on the improvement of SWB and even use SWB as the ultimate metric of social progress [5]. This potential difference becomes also a major health policy issue when one of these measures is used to set health care goals and to measure outcomes. Therefore, it is particularly important to know whether the increasingly popular HRQoL and SWB measures are competing concepts in policy setting.

The purpose of this paper is to empirically approach these two strands of health policy aims by estimating whether SWB and HRQoL measures disagree in their ability to capture the negative effects of chronic conditions. More specifically, the aim is to test whether 29 common somatic and psychiatric conditions influence SWB, even after controlling for the state of health and functional capacity as defined by two established utility-based HRQoL measures, EQ-5D and 15D. To our knowledge, this has not been systematically explored previously.

The implications of this are important especially for health policy setting. If chronic conditions are associated with lower SWB even after controlling for HRQoL, this reveals that HRQoL measures do not adequately measure all the negative effects of ill health. In particular, if there are systematic differences between chronic conditions, choosing SWB or HRQoL as a basis for rationing resources in the health care sector will systematically bias some conditions. Furthermore, if health utility scores produced by different HRQoL instruments differ between conditions, comparison of QALYs achieved with different instruments becomes also problematic.