One concern when utilizing high quality adjusted life years (QALY) to measure well being positive factors for price effectiveness analysis is that QALYs “undervalue” well being positive factors from life extension for folks with severe sickness or power 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in high quality of life (Q) and survival (S) for a brand new intervention (listed at 1) in comparison with the outdated (listed to 0).

Word that the survival positive factors 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 an alternate measure: equal worth of life years gained (evLYG). I’ve described this method beforehand right here. evLYG may be calculated as follows:

On the suitable hand aspect , the second time period is similar in each the evLYG and QALY equations, indicating that high quality of life positive factors in the course of the survival interval of the primary particular person are evaluated the identical. Nonetheless, below evLYG, survival positive factors are valued at another quantity (Qt) which may be totally different from the standard of life worth of the brand new therapy. Beneath the unique evLYG method proposed by Nord et al. (1999), survival positive factors are valued at good well being (i.e., Qt=1). Nonetheless, the Campbell et al. method utilized by ICER, units Qt=0.851, which is the same as the typical utility of the final US grownup inhabitants. Word that the ICER method assigns decrease evLYG than does the Nord method.

Beneath ICER’s implementation of evLYG, the totally different in the best way well being positive factors are measured between evLYG and QALYs may be summarized as follows:

evLYG have the important thing benefit that survival positive factors to sicker sufferers are valued extra (though much less below ICER’s implementation than below Nord).

In truth, ICER’s evaluation of 32 distinctive interventions utilizing each evLYG and QALY discovered that in 66% of instances ΔevLYG>ΔQALY, and in 34% of instances 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% greater than incremental QALYs.

One key limitation of evLYG is that high quality of life enhancements in the course of the ‘survival achieve’ interval will not be captured below evLYG.

You’ll be able to learn the complete paper right here. It’s a helpful primer each on what evLYG is and the way ICER has been utilizing evLYG in its assessments.