One concern when utilizing high quality adjusted life years (QALY) to measure well being features for price effectiveness analysis is that QALYs “undervalue” well being features from life extension for individuals with severe sickness or persistent incapacity. To see this clearly, check out the QALY method (first method under) and the way it may be decomposed into adjustments in high quality of life (Q) and survival (S) for a brand new intervention (listed at 1) in comparison with the previous (listed to 0).
Note that the survival features 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 excellent well being.
A paper by Campbell, Whittington and Pearson (2023) describes how the Institute for Clinical and Economic Review (ICER) computes another measure: equal worth of life years gained (evLYG). I’ve described this method beforehand right here. evLYG might be calculated as follows:
On the fitting hand facet , the second time period is similar in each the evLYG and QALY equations, indicating that high quality of life features through the survival interval of the primary individual are evaluated the identical. However, beneath evLYG, survival features are valued at another quantity (Qt) which might be totally different from the standard of life worth of the brand new remedy. Under the unique evLYG method proposed by Nord et al. (1999), survival features are valued at excellent well being (i.e., Qt=1). However, the Campbell et al. method utilized by ICER, units Qt=0.851, which is the same as the typical utility of the overall US grownup inhabitants. Note that the ICER method assigns decrease evLYG than does the Nord method.
Under ICER’s implementation of evLYG, the totally different in the way in which well being features are measured between evLYG and QALYs might be summarized as follows:
evLYG have the important thing benefit that survival features to sicker sufferers are valued extra (though much less beneath ICER’s implementation than beneath Nord).
In truth, 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 proportion change between an intervention dyad’s incremental QALYs and incremental evLYs was 16%. In the interventions the place ΔevLY > ΔQALY, incremental evLYs had been 25% increased than incremental QALYs.
One key limitation of evLYG is that high quality of life enhancements through the ‘survival gain’ interval aren’t captured beneath evLYG.
You can learn the complete paper right here. It is a helpful primer each on what evLYG is and the way ICER has been utilizing evLYG in its assessments.