Why measure Health-Related Quality of Life?

Although the QALY is a recognised metric used to evaluate new and innovative health technologies and optimise resource allocation via rational and explicit methodologies, especially in performing cost effectiveness analyses, a number of limitations in its application currently exist and are subject of ongoing critical debate.

Discussion centres around three major themes. These are:

a) Ethical considerations

b) Methodological Issues and Theoretical Assumptions

c) Context or Disease Specific Considerations

For each of these a few issues raised in the debate are briefly illustrated in the following.

• valuing an individual’s life over another’s:
  perfect health is difficult, if not impossible, to define, and, further, a perfect state of health does not necessarily make a life more or less valuable - for example, one cannot assume that someone who is in a wheel-chair cannot live as content as someone who isn’t and subsequently be less entitled to care
• reducing freedom of choice:
  QALYs used to justify overly restricted healthcare budgets, being more prescriptive in what healthcare options are available, system ultimately reduces autonomous patient decisions

• overly utilitarian:
  all QALYs are considered equal regardless of individual of situational circumstances. Ranking interventions on grounds of their cost per QALY gained ratio implies a quasi-utilitarian calculus to determine who will or will not receive treatment.
• equity issues:
  no account for e.g. the overall distribution of health states – particularly since younger, healthier people have many times more QALYs than older or sicker individuals. As a result, QALY analysis may undervalue treatments which benefit the elderly or others with a lower life expectancy.
  
  QALY-based system could exacerbate racial disparities in medicine because there is no consideration of genetic background, demographics, or comorbidities that may be elevated in minority racial groups that do not have as much weight in the consideration of the average year of perfect health.

• measurement techniques:

           -  measuring utility values with different methodologies can produce different results.
           -  Study participants often misunderstand utility scales.
           -  Dissimilar populations may evaluate conditions differently.
           -  Utility scores do not account for contextual factors such as severity of initial health state, prevalence of disease, parent or caregiver status, or if a population is marginalised.
          -  Definition of adequate measurements, their validity and the ability to reliably replicate them.
          -  QALY is the product of utility and time, and time is a non-zero variable. However, in QALY models, utility is assigned an arbitrary scale from 0 (death) to 1 (perfect health) and this use of 0 prevents arithmetic operations such as division and multiplication. A potential solution to this would be measuring time and utility using similar units of measurement, which would translate into more meaningful and accurate outcomes.

• employment of league table comparisons of QALYs for different interventions (comparing heterogeneous populations and time periods):
  Theoretically, a QALY calculated for angina treatment in 1997 in the UK may well have different results compared to a QALY calculation for angina in Germany in 2005.

• discrimination against new and innovative treatments:
  the QALY model requires utility independent, risk neutral constant cost effectiveness and therefore issues a fixed cost for an intervention that does not factor in a potential reduction in costs as technology advances and interventions are refined, such as those falling within the remit of regenerative medicine, which are often expensive initially but significantly reduce in cost over time. Because of these theoretical assumptions, the meaning and usefulness of the QALY is debated.

• limit research on treatments for rare disorders:
  upfront costs of the treatments tend to be higher. Officials in the United Kingdom were forced to create the Cancer Drugs Fund to pay for new drugs regardless of their QALY rating because innovation had stalled since NICE was founded.

The European Consortium in Healthcare Outcomes and Cost-Benefit Research (ECHOUTCOME) ran a major study on QALYs as used in HTA. They concluded that "preferences expressed by the respondents were not consistent with the QALY theoretical assumptions" that quality of life can be measured in consistent intervals, that life-years and quality of life are independent of each other, that people are neutral about risk, and that willingness to gain or lose life-years is constant over time.[1] . ECHOUTCOME also released "European Guidelines for Cost-Effectiveness Assessments of Health Technologies," which recommended not using QALYs in healthcare decision making.[2] . Instead, the guidelines recommended that cost-effectiveness analyses focus on "costs per relevant clinical outcome." Instead, the guidelines recommended that cost-effectiveness analyses focus on "costs per relevant clinical outcome."

QALYs have limited value where quality of life is a major consideration but survival is not, thus limiting the utility of the QALY in evaluating the effects of many chronic but not fatal diseases.

In general, younger, healthier groups of people will have many times more QALYs than groups of older, more infirm individuals therefore QALY calculations may undervalue treatments which benefit the elderly or other groups with a lower life expectancy.