Equal Value of Life Years Gained

The Equal Value of Life Years Gained or evLYG is a generic measure used to determine how much a medical treatment can extend the life of the patient. Unlike other healthcare metrics, the evLYG does not consider the quality of life for the patient; it exclusively considers the length of life. It is used in economic evaluation to determine the added time a treatment may give a patient.^[1] Critics argue the evLYG measurement is flawed because it values a medication based solely on the added years of life. A higher priced drug that both extends life and adds two years of life receives the same evLYG score as a lower priced drug that adds two years but does not improve life.^[2]

The evLYG is used in concert with the Quality-Adjusted Life Year (QALY) to reduce the discriminatory characteristics of the QALY, which has been criticized as being ageist or ableist for placing more value on the lives of younger people without disability.^[3] The Institute for Clinical and Economic Review (ICER) uses a hybrid of the QALY and the evLYG to determine treatment prices.^[4][5] Critics have argued the use of the evLYG along with the QALY does not do enough to fully eliminate the discriminatory aspects of the QALY measurement.^[6]

Calculation

The evLYG measures the cost of a treatment to prolong life for a year, without considering the quality of life of that year. All additional years of life gained from a treatment are considered to be “full health,” regardless of the state of the patient.^[7] “Full health” is defined as the average health of the population, and set at 0.851 on a 0-1 scale.^[8] In effect, this measure makes treatments appear to have a greater impact if they extend the patients life, even if the patient themselves is disabled, elderly, or terminally ill.

Use

The evLYG is not in mainstream use, and instead remains a measuring tool advocated for by the Institute for Clinical and Economic Review. The Centers for Medicare and Medicaid Services has announced that they are considering using the evLYG metric for medicare drug price negotiations, but the decision to implement the metric has not yet been made. ^[9]

Criticism

While evLYGs were introduced to calm criticism that the QALY metric could be discriminatory, there has still been significant criticism of the evLYG metric.

Critics argue that the evLYG relies on generic Patient Reported Outcomes for specific medical cases. Specifically, that the weightings for the evLYG metric were constructed by people unfamiliar with the specific patients being measured. In other words, the metric is attempting to be a “one-size-fits-all” solution for a very diverse patient group. ^[10]

Other critics argue that the evLYG metric ignores additional dimensions of value that can be provided by a specific treatment. For example, two treatments may provide the same extension of life, but one treatment might reduce the burden on the healthcare system while the other does not. These two treatments would be seen as providing the same value under the evLYG metric, despite the additional benefits provided by the latter. ^[11]

Another criticism is that the evLYG metric ignores the quality of a patient’s health. Not every medical condition is life-threatening, and the evLYG  metric would be useless in those cases. For example, a treatment for blindness would be considered useless under the evLYG metric, since treating blindness doesn’t directly expand the patient’s lifespan. ^[12]

References

1. "ICER to use new metric to assess drug cost-effectiveness". The Pharma Letter. Retrieved 20 July 2021.
2. Cohen, Joshua; Ollendorf, Daniel; Neumann, Peter. "Will ICER's Response to Attacks on the QALY Quiet the Critics?". Center for the Evaluation of Value and Risks in Health. Retrieved 20 July 2021.
3. Carlson, Josh; Brouwer, Elizabeth; Kim, Eunice; Wright, Phoebe; McQueen, Brett (2020). "Alternative Approaches to Quality-Adjusted Life-Year Estimation Within Standard Cost-Effectiveness Models: Literature Review, Feasibility Assessment, and Impact Evaluation". Value in Health. 23 (12): 1523–1533. doi:10.1016/j.jval.2020.08.2092. PMID 33248507. S2CID 225121375.
4. Cohen, Joshua. "A QALY Is A QALY Is A QALY, Or Is It?". Forbes. Retrieved 20 July 2021.
5. "Cost-Effectiveness, the QALY, and the evLYG". ICER. Retrieved 20 July 2021.
6. "An Introduction to the Institute for Clinical and Economic Review (ICER) and Their Implications for New Sickle Cell Disease Treatments: A Primer on the Issues" (PDF). Sickle Cell Consortium. Retrieved 20 July 2021.
7. "2020-2023 Value Assessment Framework" (PDF). Institute for Clinical and Economic Review. December 8, 2021.
8. "Demystifying ICER's Equal Value of Life Years Gained Metric". ISPOR | International Society For Pharmacoeconomics and Outcomes Research. Retrieved 2023-12-11.
9. Seshamani, Meena (June 30, 2023). "Medicare Drug Price Negotiation Program: Revised Guidance, Implementation of Sections 1191 – 1198 of the Social Security Act for Initial Price Applicability Year 2026" (PDF).
10. "Methods Update: Value Assessment Framework". ICER. Retrieved 2023-12-11.
11. "Methods Update: Value Assessment Framework". ICER. Retrieved 2023-12-11.
12. "Methods Update: Value Assessment Framework". ICER. Retrieved 2023-12-11.