A Comparison of Outcomes Measures in Cost-Effectiveness Analysis: Three Applications Within Oncology

OBJECTIVES: Quality-adjusted life-years (QALYs) are the predominant measure of health benefit in health technology assessment (HTA) processes, despite limitations including potential discrimination against elderly and disabled populations.

Equal value life years (evLYs) and health years in total (HYT) have been proposed as alternatives.

We compared these measures with QALYs using three economic models for oncology indications, to better understand the implications of using alternatives to QALYs for HTA.

METHODS: Three economic models of treatments (for renal cell carcinoma, myeloid leukemia and lung cancer) were created using our in-house platform, known as PfyDICE. These models were used to compare outcomes based on QALYs with those based on life-years (LYs), evLYs, and HYTs.

RESULTS: Incremental HYTs consistently yielded the most favorable treatment benefit (13-46% higher than incremental QALYs).

Absolute and incremental QALYs and evLYs were generally closely aligned. The one exception was for lung cancer where, compared to other indications, the average utilities were lower and extension in survival was higher, which resulted in higher incremental evLYs (22%) than QALYs.

The relationship between QALYs and LYs was more volatile and depended on changes to the time spent in progression free and progressed disease states respectively.

CONCLUSIONS: Among the indications evaluated, this study found that HYT were consistently higher than QALYs as they add life-years gained to the QOL gain; evLYs were generally aligned with QALYs estimated. While no additional data was needed to calculate these alternative outcome measures, a drawback of this is that no further data is incorporated that might influence HTA decisions. Alternative measures can be used alongside the traditional QALY approach but do not fully remedy the perceived drawbacks of the QALY. To that end, broad understanding of the limitations of alternatives to the QALY and of disease specific variability is needed by HTA bodies and access policy decision-makers.