#### Pages within the "support" section:

- Support home
- Glossary
- Model parameters
- Summary
- 1. Introduction
- 1.1 General framework
- 1.2 Relationship to the BRAFO tiered approach
- 2. Problem formulation
- 2.1 Dietary scenarios
- 2.2 Population
- 3. Common metrics for integration of risks & benefits
- 3.1 DALY versus QALY.
- 3.2 Alternative approaches for calculating DALY/QALYs
- 4. Main elements of the Qalibra framework
- 5. When is use of the Qalibra framework appropriate?
- 6. Calculation of DALYs for quantal health effects
- 7. Calculation of DALYs for continuous health effects
- 8. Calculation of QALYs for quantal and continuous health effects [current page]
- 9. Recurrent effects
- 10. Effects on the next generation
- 11. Multiple effects on the same health endpoint
- 12. Calculating the net health impact of a dietary change
- 13. Direct health loss calculations for a single individual
- 14. Data needed as inputs to the Qalibra framework
- 14.1 Individuals and their attributes
- 14.2 Life expectancy
- 14.3 Health effects to be quantified
- 14.4 Dietary intakes
- 14.5 Probability of quantal effects
- 14.6 Probability and magnitude of continuous effects
- 14.7 Probabilities of recovery and death
- 14.8 Duration of disease
- 14.9 Severity of effect (disease weights)
- 15. Addressing uncertainty in risk-benefit assessment
- 15.1 Qualitative evaluation of uncertainties
- 15.2 Quantitative evaluation of uncertainties
- 15.3 Probabilistic treatment of uncertainty in Qalibra
- 16. Treatment of variability in the Qalibra framework
- 17. Treatment of dependencies in Qalibra framework
- 18. Presentation of results
- 19. Interpretation of results
- 20. Risk management considerations
- 21. Final remarks
- Acknowledgements
- References

# 8. Calculation of QALYs for quantal and continuous health effects

Whereas DALYs are intended for representing health losses, QALYs are intended for representing remaining health, after allowing for any disease(s) that may be present.

The directly attributable health loss approach does not attempt to model the net health of the individual taking account of all concurrent diseases. However, it can be used to estimate potential health losses in terms of lost QALYs, subject to the same limitation as before, that it considers each disease in isolation from others.

For a quantal effect, the QALY loss can be calculated as:

_{
}

Equation (3)

For a continuous effect, the QALY loss can be calculated as:

_{
}

Equation (4)

where

*
q
*
= 1- QALY weight for a quantal effect

*q(effect)*
= 1 – QALY weight expressed as a function of continuous effect size,

and where the QALY weights can differ between individuals who recover, die or live with the disease (as shown by the subscripts in equation 4).