Severity of illness and priority setting in healthcare: A review of the literature

Abstract

Background

It is widely assumed that the principal objective of healthcare is to maximise health. However, people may be willing to sacrifice aggregate health gain in order to direct resources towards those who are worst off in terms of the severity of their pre-treatment health state.

Objectives

This paper reviews the literature on severity in the context of economic evaluation, with the aim of establishing the extent to which popular preferences concerning severity imply a departure from the health maximisation objective.

Methods

Data were obtained using a keyword search of major databases and a hand search of articles written by leading researchers in the subject area.

Results

The empirical evidence suggests that people are, on the whole, willing to sacrifice aggregate health in order to give priority to the severely ill. However, there remain unresolved issues regarding the elicitation and interpretation of severity preferences (and indeed popular preferences generally).

Conclusions

The use of severity as a priority setting criterion is supported by a large number of empirical studies of popular preferences. Further work is needed, however, to accurately estimate the strength of this support.

Introduction

It is widely assumed by health economists that the principal objective of healthcare is to maximise health using available resources [1]. Since the quality-adjusted life year (QALY) has been developed to provide a generic measure of health effect, it follows that healthcare resource allocation should seek to maximise the number of QALYs generated. In cost-utility analysis (CUA), the overall health benefits of a treatment are calculated by aggregating the QALY gains accruing to individual patients using a simple, unweighted summation. This is commonly known as the QALY maximisation rule [2]. It entails distributive neutrality—that is, it does not incorporate concerns for how benefits are distributed across individuals. Culyer refers to this position as ‘QALY egalitarianism’—all QALYs are of equal social value, regardless of to whom they accrue and the context in which they are enjoyed [3]. In other words, a ‘QALY is a QALY is a QALY’ under all circumstances. The National Institute for Health and Clinical Excellence (NICE), the organisation responsible for providing advice on the cost-effective use of healthcare resources in England and Wales, formally documents this rule in its methods guide [4].

However, maximising health may not be the only purpose of healthcare. For example, the UK's National Health Service (NHS) also has equity objectives such as seeking to “improve the health of the poorest fastest” [5]. NICE recognises that society may have preferences regarding the use of healthcare funding that involve some sacrifice of total health gains in order to achieve a more equitable distribution of health [6]. However, there is currently no consensus on what might provide a socially acceptable basis for deviating from the QALY maximisation rule. For a particular value judgement to be incorporated into the methodology it must demonstrate ‘social legitimacy’ [7]—that is, there must be systematic evidence of societal support for the change. In line with the NHS's increasing emphasis on the need for public involvement in decision-making processes [8], [9], NICE's position on social value judgements is informed by the findings of empirical research on popular preferences and the work conducted by its Citizens Council (a representative panel of the general population who meet biannually to discuss questions related to social values within healthcare) [10].

There are a number of grounds for deeming that the social value of healthcare depends on something other than the sum of the individual health gains of affected patients. Schwappach presents a selection of potential sources of social value, classifying them as (i) factors concerning specific characteristics of the patient or treatment, and (ii) factors concerning the nature of the health improvement [11]. Several researchers have attempted to capture popular preferences regarding these factors through empirical investigation. One factor that has been the focus of much recent attention is the severity of the patient's pre-treatment health—for many, there is intrinsic value in treating sufferers of severe ill health that goes beyond the individual health gain produced by the treatment.

The importance of severity is already well established in a number of industrialised countries. In 1986, the Norwegian government commissioned a panel of healthcare politicians, health administrators, healthcare personnel and patient representatives to set out prioritisation guidelines for the Norwegian National Health Service [12]. The panel concluded that severity should be of primary importance when prioritising between patients and should be considered together with the effectiveness of treatment. Other countries whose reimbursement decisions are informed by considerations of severity include Finland, France, Germany, Spain and Sweden [13], [14], [15], [16].

This paper provides an analysis of the published literature on severity in the context of economic evaluation, with the aim of establishing the extent to which popular preferences concerning severity imply a departure from the health maximisation objective. Although the question of how extensive public involvement in healthcare decision-making should be remains unresolved, it is clearly important for decision makers to be made aware of popular values. At a minimum, the results of societal preference studies can be used to inform them about the extent of consensus or disagreement amongst the general population. Richardson and McKie propose that allocation principles should be derived using an iterative process whereby the results of empirical studies of popular preferences are subjected to ethical scrutiny, with further qualitative and quantitative re-testing based on the results of this scrutiny [17].

Severity is a topical issue that is highly relevant to current UK healthcare policy. In early 2008, the NICE Citizens Council met to discuss the role that severity should play in decision-making processes [18] (indeed, NICE's chief executive Andrew Dillon is quoted as having referred to the topic as “the big one”). Furthermore, two recent NICE-commissioned research projects on the societal value of health gains both conducted preliminary qualitative research which identified severity as being a relevant attribute in the context of healthcare resource allocation [19], [20].

In the following paper, Section 2 describes the methodology used to conduct the literature search. Section 3 sets out the results of the search, first by briefly reporting how severity is defined in the literature, and then by providing a tabular summary of the available empirical evidence on severity-related popular preferences. Section 4 examines four key discussion points arising from the evidence. Finally, Section 5 summarises the findings of the paper and establishes some recommendations for further research.