Why measure Health-Related Quality of Life?


1. Why measure Health-Related Quality of Life?

There are many reasons why we might want to measure HRQoL:

  • Patients and healthcare providers as well as payers are interested in the added value a technology (health intervention or use of health technology) has to offer. HRQoL can serve as a common measure of gains from any technology as perceived by patients. Patient groups can use these measures to compare the values of new technologies.
  • HRQoL measures are also often used in relation to the costs of new health technologies in an economic evaluation to support decision-making in HTA processes.
  • HRQoL measures provide useful information to care providers as they can be used to screen and monitor patients for psychosocial problems or when auditing healthcare practice.
  • HRQoL measures can be used in population surveys of perceived health problems or other aspects of health-services or evaluation research.
  • Regulators can use HRQoL measures to support their assessments of new technologies. In fact, in some instances HRQoL changes are accepted as primary or secondary endpoints in clinical trials if justified and explicitly detailed in trial protocols.

For policy makers, who are supposed to decide how to allocate resources in healthcare, and HTA bodies, being able to appraise the value that a new technology may bring compared to other technologies across various types of patients is useful and may support their assessments or decisions. Payers are interested in science-based decisions and quantifying the gains that a treatment can provide for a patient. A generic instrument to measure HRQoL allows a numeric HRQoL score to be calculated but such instruments require qualitative research to design and develop them.

What is a Quality-Adjusted Life Year (QALY)?

Policy makers and HTA organisations may use a numeric HRQoL score for instance in the calculation of a Quality-Adjusted Life Year (QALY) – although there are ongoing debates about how to use QALYs in healthcare decision making or whether or not to use them at all.

The quality-adjusted life year (QALY) is a generic measure of disease burden, including both the quality and the length of life lived while also taking into account any changes in the health-related quality of life (HRQoL). The QALY therefore is a measure of the value of health outcomes (utility value, see below box) to the people who experience them and is an attempt to combine two different attributes associated with treatment - length of life and quality of life - into a single score/number (an index) that can be compared across different types of treatments (interventions).

One QALY equates to one year in perfect health (the utility value set to 1 (or 100%)). One year of less than perfect health has a quality of life (or utility value) between 0 – 1 (a percentage (in decimals) between 0 and 1). Death has a utility value of 0 (a respondent could choose to record a score below zero – worse than death – where, for instance, they are experiencing severe distress and/or possibly a terminal illness, although many people with terminal illnesses do not have utilities <0).

Health Utility Measures

Health utility measures are values (or utility weights) associated with a given state of health by the years lived in that state or preferences that patients attach to their health state. Utility values are generic HRQoL measures (HRQoL weights), which are determined either directly, through in-person interviews using measures such as standard gamble, time tradeoff, or willingness to pay, or indirectly through HRQoL instruments. The direct measures involve comparisons against an external metric that a person would be willing to trade to improve their current health state, such as the risk of death (standard gamble), years of life (time tradeoff), or amount of money (willingness to pay). Indirect methods of determining the weight associated with a particular health state use standard descriptive systems such as the EuroQol five dimension questionnaire (EQ-5D) (categorises health states according to five dimensions: mobility, self-care, usual activities (e.g. work, study, homework or leisure activities), pain/discomfort and anxiety/depression). An algorithm is then used to compute a utility score integrating both individual and community perspectives.