What are QALYs?

QALY stands for Quality-Adjusted Life Year.

It is a way of measuring how much benefit a medical treatment provides by combining:

• Length of life
• Quality of life

Simple Definition

1 QALY = 1 year lived in perfect health

QALYs are used by the NHS and organisations such as National Institute for Health and Care Excellence (NICE) to decide whether new treatments are cost-effective.

Why are QALYs Important?

The NHS has limited resources and cannot fund every treatment available.

QALYs help healthcare systems decide:

• Which treatments provide the greatest benefit
• Whether expensive drugs are worth funding
• How NHS resources should be allocated fairly

They are commonly used when assessing:

• Cancer drugs
• Rare disease treatments
• Surgical procedures
• Long-term therapies

The QALY Formula

\text{QALY} = \text{Time in Health State} \times \text{Quality of Life Score}

Understanding the Quality-of-Life Score

The quality-of-life score is also called the:

HRQL Score

(Health-Related Quality of Life)

This score ranges from:

The score considers factors such as:

• Pain
• Mobility
• Mental health
• Independence
• Daily functioning

QALY (Quality-Adjusted Life Year) combines both the quantity and quality of life into a single measure.

Formula

QALYs=Years of Life × Quality of Life Weight

Where:

• 1.0 = perfect health
• 0.5 = health state valued at 50% of perfect health
• 0 = death
• Negative values are possible for states considered worse than death

QUALY CALCULATIONS

Example 1: Simple Calculation

A patient receives a treatment that gives them 10 additional years of life at a quality-of-life score of 0.8.

10×0.8=8 QALYs

Answer: The treatment provides 8 QALYs.

Example 2: Comparing Two Treatments

Treatment A

• 8 years of life
• Quality of life = 0.9

8×0.9=7.2 QALYs

Treatment B

• 10 years of life
• Quality of life = 0.6

10×0.6=6.0 QALYs

Answer: Treatment A provides more QALYs (7.2 vs 6.0).

Example 3: Different Health States Over Time

A patient experiences:

• 5 years at quality of life = 0.8
• Followed by 3 years at quality of life = 0.5

Calculation:

(5×0.8)+(3×0.5)

4+1.5=5.5 QALYs

Answer: Total = 5.5 QALYs

Example 4: Cost per QALY (NICE Style)

A new drug costs £30,000 and produces 2 additional QALYs.

Cost per QALY=£30,0002\2

=£15,00 per QALY

Answer: £15,000 per QALY gained.

Example 5: ICER Calculation(Incremental Cost-Effectiveness Ratio)

Current treatment:

• Cost = £20,000
• QALYs = 4

New treatment:

• Cost = £35,000
• QALYs = 5

Incremental Cost

£35,000−£20,000=£15,000£35,000 - £20,000 = £15,000

Incremental QALYs

5−4=1

ICER

ICER=£15,0001\1 = 15,000 per QALY

Answer: The new treatment costs £15,000 per additional QALY gained.

NICE Thresholds

National Institute for Health and Care Excellence generally considers treatments:

However, exceptions can occur for:

• Rare diseases
• End-of-life treatments
• Major quality-of-life improvements

Advantages of QALYs

1. Helps Allocate NHS Resources

QALYs allow the NHS to compare treatments objectively.

2. Combines Quantity AND Quality of Life

Unlike simple survival rates, QALYs consider:

• How long patients live
• How well they live

3. Allows Easy Comparison

Different treatments for different diseases can be compared using one standard measure.

4. Encourages Evidence-Based Decisions

QALYs support fairer and more transparent healthcare funding decisions.

Limitations of QALYs

1. Quality of Life is Subjective

Different patients value health states differently.

For example:

• One person may value mobility most
• Another may value independence or mental wellbeing

2. Can Disadvantage Older or Disabled Patients

Some critics argue QALYs may unfairly favour:

• Younger patients
• Healthier individuals

because they may gain more future QALYs.

3. Difficult to Measure Human Experience

Not all benefits fit neatly into a numerical score.

Examples:

• Emotional wellbeing
• Family relationships
• Ability to work
• Personal independence

4. Ethical Concerns

Some expensive treatments may greatly help small patient groups but still fail NICE approval because the cost per QALY is too high.

Ethical Principles Linked to QALYs

Justice

QALYs aim to distribute NHS resources fairly.

However:

Is it fair to value some lives more highly than others?

Beneficence

Approving effective treatments improves patient wellbeing.

Non-Maleficence

Rejecting expensive treatments may deny patients potentially beneficial care.

Autonomy

Patients may want treatments that the NHS refuses to fund.

Real NHS Example: Orkambi

Orkambi is a drug used for cystic fibrosis.

It significantly improved patients’ quality of life, but NICE initially refused approval because:

• The cost per QALY was extremely high
• It exceeded normal NHS cost-effectiveness thresholds

This demonstrates the ethical tension between:

• Cost control
• Patient benefit

QALYs vs DALYs

DALY stands for:

Disability-Adjusted Life Year

Medical Interview Questions and Tips

Common questions include:

• What is a QALY?
• Why does NICE use QALYs?
• What are the ethical concerns surrounding QALYs?
• Should expensive treatments always be funded?
• Do QALYs discriminate against certain groups?
• How should the NHS allocate limited resources?
• What are the strengths and weaknesses of QALYs?

Keep explanations simple

Avoid overcomplicating calculations.

Link QALYs to NHS resource allocation

This shows wider NHS understanding.

Discuss BOTH benefits and limitations

Balanced answers score highly in interviews.

Mention Ethics

Especially:

• Justice
• Fairness
• Equality
• Resource allocation

Key Takeaway

QALYs are a healthcare tool used to measure:

• How long people live
• How good their quality of life is

They help the NHS decide:

Which treatments provide enough benefit to justify their cost.

Although useful, QALYs also raise important ethical questions about fairness, equality, and how society values health and life.

Fifteen Questions and Answers

1. What is a QALY?

Model Answer

A QALY stands for a Quality-Adjusted Life Year. It is a measure used in healthcare to assess the value of medical treatments by combining both the quantity and quality of life gained from an intervention.

One QALY is equal to one year lived in perfect health.

For example, if a treatment gives a patient two extra years of life at a quality-of-life score of 0.5, this would equal one QALY.

QALYs are used by National Institute for Health and Care Excellence to help determine whether treatments are cost-effective for the NHS.

2. Why does NICE use QALYs?

Model Answer

National Institute for Health and Care Excellence uses QALYs to help decide whether new treatments provide sufficient benefit compared with their cost.

Because NHS resources are limited, NICE must ensure funding is used efficiently and fairly. QALYs allow treatments for completely different diseases to be compared using one standard measurement.

This helps the NHS prioritise treatments that improve both the length and quality of patients’ lives while remaining cost-effective.

3. How are QALYs calculated?

Model Answer

QALYs are calculated by multiplying:

• The amount of time spent in a health state
• By the quality-of-life score for that health state

QALYs=Years of Life×Quality of Life WeightFor example:

• A patient lives for 5 years
• Their quality-of-life score is 0.8

5 x 0.8 = 4 QALYs

This means the treatment provides the equivalent of 4 years in perfect health.

4. What are the advantages of QALYs?

Model Answer

One major advantage of QALYs is that they provide a standardised way to compare treatments across different medical conditions.

They also consider both quality and quantity of life, rather than simply survival alone. This makes healthcare decision-making more patient-centred.

QALYs also support evidence-based resource allocation by helping the NHS identify which treatments provide the greatest benefit relative to cost.

Additionally, the calculations are relatively straightforward and allow policymakers to make transparent funding decisions.

5. What are the limitations of QALYs?

Model Answer

There are several limitations to QALYs.

First, quality of life is subjective, and different patients may value health states differently.

Second, QALYs may unintentionally disadvantage older patients or people with disabilities because they may gain fewer future QALYs from treatment.

Third, many important aspects of life, such as emotional wellbeing or family relationships, are difficult to measure numerically.

Finally, some expensive treatments for rare diseases may greatly benefit patients but still fail cost-effectiveness thresholds, raising ethical concerns about fairness.

6. Which ethical principle is most relevant to QALYs?

Model Answer

The ethical principle most closely associated with QALYs is justice.

QALYs aim to distribute NHS resources fairly by ensuring treatments funded by the NHS provide good value for money.

However, there are ethical concerns because QALYs may place greater value on people who can gain more years of healthy life, potentially disadvantaging older or chronically ill patients.

The principles of beneficence and non-maleficence are also relevant because treatments approved through QALYs may improve patient wellbeing, while treatments rejected due to cost may deny beneficial care.

7. What is an ICER?

Model Answer

ICER stands for Incremental Cost-Effectiveness Ratio.

It measures how much extra money is required to gain one additional QALY from a new treatment compared with an existing treatment.

The formula is:

\text{ICER} = \frac{\text{Difference in Cost}}{\text{Difference in QALYs}}

For example:

• A treatment costs £20,000 more
• It provides 2 extra QALYs

\frac{£20,000}{2}=£10,000\text{ per QALY}

NICE uses ICER values to determine whether treatments are cost-effective.

8. Do you think QALYs are fair?

Model Answer

I think QALYs are useful because they provide an objective and structured way to allocate limited NHS resources fairly. Without systems like QALYs, healthcare funding decisions could become inconsistent or subjective.

However, they are not perfect. QALYs may unintentionally disadvantage certain groups, such as older patients, disabled individuals, or people with chronic illnesses, because these groups may gain fewer QALYs from treatment.

Therefore, while QALYs are valuable tools, they should not be the only factor used in healthcare decisions. Ethical considerations, patient circumstances, and wider societal benefits should also be considered.

9. How do QALYs affect patient care?

Model Answer

QALYs can positively affect patient care by helping approve effective treatments that improve quality and length of life.

However, they can also restrict access to expensive treatments if those treatments are not considered cost-effective.

This means some patients may be unable to receive potentially beneficial therapies through the NHS.

For example, some rare disease medications have very high costs per QALY, creating difficult ethical dilemmas between affordability and patient benefit.

10. Why is quality of life difficult to measure?

Model Answer

Quality of life is difficult to measure because it is highly subjective and varies between individuals.

Different people value aspects of life differently. For example:

• One patient may prioritise mobility
• Another may value independence
• Another may focus on pain reduction

Cultural background, mental health, social support, and personal experiences can all influence how someone perceives their quality of life.

This makes it challenging to assign one universal numerical value to health states.

11. What is the difference between a QALY and a DALY?

Model Answer

A QALY measures healthy life gained, while a DALY measures healthy life lost due to illness or disability.

QALYs are mainly used to evaluate healthcare treatments and interventions. Higher QALYs are better.

DALYs, or Disability-Adjusted Life Years, are commonly used in public health to assess disease burden across populations. Lower DALYs are better.

So essentially:

• QALYs focus on health gained
• DALYs focus on health lost

12. Should expensive treatments for rare diseases always be funded?

Model Answer

This is a complex ethical issue.

On one hand, patients with rare diseases deserve access to effective treatments, and denying treatment purely because a condition is uncommon could be considered unfair.

On the other hand, NHS resources are limited, and funding extremely expensive treatments may reduce the resources available for treatments that benefit larger numbers of patients.

I think decisions should balance:

• Clinical effectiveness
• Patient quality of life
• Fairness
• Overall NHS resource allocation

This highlights the difficult balance between individual patient needs and population-level healthcare planning.

13. How would you explain QALYs simply to a patient?

Model Answer

I would explain that QALYs are a way of measuring how much a treatment improves both the length and quality of someone’s life.

For example, living one year in perfect health equals one QALY. If someone lives with illness or disability, the QALY value would be lower.

The NHS uses QALYs to help decide which treatments provide enough benefit to justify their cost so that healthcare resources can be used fairly.

14. Can QALYs discriminate against certain groups?

Model Answer

Some critics argue that QALYs may unintentionally disadvantage older adults, disabled people, or patients with chronic illnesses because these groups may gain fewer additional healthy years from treatment.

This raises concerns about equality and fairness.

However, supporters argue that QALYs are designed to maximise overall health benefits across the population rather than discriminate against individuals.

Because of these ethical concerns, healthcare decisions should not rely solely on QALYs and should also consider wider ethical and social factors.

15. Why are QALYs relevant to medical interviews?

Model Answer

QALYs are relevant because they demonstrate understanding of:

• NHS resource allocation
• Medical ethics
• Cost-effectiveness
• Healthcare policy

They are particularly useful in discussions about:

• Expensive treatments
• Organ transplantation
• Drug funding
• Justice and fairness in healthcare

Understanding QALYs shows awareness of the challenges involved in balancing patient care with limited NHS resources.

Useful Links

https://www.nice.org.uk/process/pmg6/chapter/assessing-cost-effectiveness

https://www.england.nhs.uk/ourwork/freedom-to-speak-up/?utm_source=chatgpt.com

https://link.springer.com/article/10.1186/1472-6963-11-8?utm_source=chatgpt.com

https://www.ncbi.nlm.nih.gov/books/NBK274322/?utm_source=chatgpt.com