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3. Why measure Health-Related Quality of Life?

1. Why measure Health-Related Quality of Life?

There are several important reasons to measure health-related quality of life (HRQoL).

These measures capture how patients perceive their health status and the impact of medical interventions, offering valuable insights for multiple stakeholders:

🔹 Patients, Providers, and Payers
  • Patients and healthcare providers are interested in understanding the added value of a health intervention from the patient’s perspective.
  • Payers rely on HRQoL to assess the perceived benefit of new technologies in order to inform reimbursement decisions.
  • Patient groups can use HRQoL data to compare the value of emerging technologies.
🔹 Economic Evaluation and HTA
  • HRQoL measures are often used in economic evaluations to compare the cost-effectiveness of different health technologies.
  • They contribute to the comparability of interventions across disease areas in health technology assessment (HTA).
🔹 Clinical Practice and Research
  • In clinical settings, HRQoL instruments can help screen for psychosocial concerns and support patient monitoring.
  • They are also useful in auditing healthcare practice
  • HRQoL measures can be used in population surveys of perceived health problems or other aspects of health-services or evaluation research.
🔹 Regulatory Applications
  • Regulators may consider HRQoL changes as primary or secondary endpoints in clinical trials, provided these are justified and pre-specified in the protocol.
🔹 Instruments and Measurement
  • Generic instruments for measuring HRQoL yield a numerical score, facilitating comparisons across conditions.
  • These instruments require qualitative research during their development to ensure they capture relevant domains of patient experience.

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

The Quality-Adjusted Life Year (QALY) is is a generic measure of disease burden including:

The QALY therefore is a measure of the value of health outcomes (health utility measures explained below) 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).

  • A single QALY equates to one year in perfect health — i.e. a utility value of 1.0 (or 100%).
  • A year lived in less-than-perfect health has a utility value 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).
The Quality-Adjusted Life Year (QALYs) are widely used by policymakers and HTA organisations to measure the value of medical interventions, although debate continues about their role and appropriateness in healthcare decision-making.

Health Utility Measures

Health utility measures are values that express how individuals prefer or value different health states, taking into account either the time spent in those states or the preferences people assign to them.

They can be derived in two main ways:

🔹 Direct Methods

Utility values are elicited through structured questions that ask individuals to make trade-offs involving: 

  • Risk of death → Standard Gamble
  • Length of life → Time Trade-Off
  • Monetary value → Willingness to Pay

The direct measures involve comparisons against an external metric (of risk, time and money) that a person would be willing to trade to improve their current health state and can be determied 

🔹 Indirect Methods

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)

This tool evaluates five dimensions of health:

  • Mobility
  • Self-care
  • Usual activities (e.g., work, study, leisure)
  • Pain/discomfort
  • Anxiety/depression

An algorithm is then applied to translate an individual’s responses into a single utility score, reflecting both individual preferences and broader societal values.

📌 Examples of QALY Use

Examples of QALY use are listed below and should be read in conjunction with Section 3: “Why measure Health-Related Quality of Life?”. While not exhaustive, this list highlights some of the most common applications. Pay particular attention to the final point, which illustrates how QALYs are applied by an HTA body (e.g. NICE [1]).

QALYs can be used to

  • quantify the effectiveness of a new treatment (e.g., new medication) compared to the current treatment for a particular condition.
  • to compare the health benefit of a new treatment for one condition with the health benefit of a new treatment for a different condition. For instance, the QALY permits comparison of a new cancer therapy with the health effect of a new Parkinson's medication.
  • to inform health insurance coverage determinations, treatment decisions, to evaluate programmes, and to set priorities for future programmes
  • to combine data on medical costs with QALYs in cost-utility analysis to estimate the cost-per-QALY associated with a health care intervention. This parameter can be used to develop a cost-effectiveness analysis of any treatment and can be used to allocate healthcare resources, often using a threshold approach. (in the United Kingdom, the National Institute for Health and Care Excellence (NICE), which advises on the use of health technologies within the National Health Service, has used "£ per QALY" to evaluate their utility).

In summary, QALY is commonly used in health economic evaluations as a means of quantifying the health effect of a medical intervention or a prevention programme and ultimately to help payers allocate healthcare resources.