One concern when utilizing high quality adjusted life years (QALY) to measure well being good points for value effectiveness analysis is that QALYs “undervalue” well being good points from life extension for individuals with severe sickness or continual incapacity. To see this clearly, check out the QALY components (first components under) and the way it may be decomposed into modifications in high quality of life (Q) and survival (S) for a brand new intervention (listed at 1) in comparison with the outdated (listed to 0).
Be aware that the survival good points are solely valued on the high quality of life that the intervention can acheive (Q1t). Thus, survival enhancements for sufferers who stay having a poor high quality of life are devalued relative to those that woudl be in good and even good well being.
A paper by Campbell, Whittington and Pearson (2023) describes how the Institute for Medical and Financial Evaluate (ICER) computes another measure: equal worth of life years gained (evLYG). I’ve described this strategy beforehand right here. evLYG might be calculated as follows:
On the proper hand facet , the second time period is similar in each the evLYG and QALY equations, indicating that high quality of life good points through the survival interval of the primary individual are evaluated the identical. Nevertheless, beneath evLYG, survival good points are valued at another quantity (Qt) which might be completely different from the standard of life worth of the brand new therapy. Underneath the unique evLYG strategy proposed by Nord et al. (1999), survival good points are valued at good well being (i.e., Qt=1). Nevertheless, the Campbell et al. strategy utilized by ICER, units Qt=0.851, which is the same as the typical utility of the final US grownup inhabitants. Be aware that the ICER strategy assigns decrease evLYG than does the Nord strategy.
Underneath ICER’s implementation of evLYG, the completely different in the best way well being good points are measured between evLYG and QALYs might be summarized as follows:
evLYG have the important thing benefit that survival good points to sicker sufferers are valued extra (though much less beneath ICER’s implementation than beneath Nord).
In reality, ICER’s evaluation of 32 distinctive interventions utilizing each evLYG and QALY discovered that in 66% of circumstances ΔevLYG>ΔQALY, and in 34% of circumstances ΔevLYG=ΔQALY. The imply share change between an intervention dyad’s incremental QALYs and incremental evLYs was 16%. Within the interventions the place ΔevLY > ΔQALY, incremental evLYs have been 25% increased than incremental QALYs.
One key limitation of evLYG is that high quality of life enhancements through the ‘survival achieve’ interval should not captured beneath evLYG.
You may learn the total paper here. It’s a helpful primer each on what evLYG is and the way ICER has been utilizing evLYG in its assessments.