Real-world impact of disease on functioning and activity: what is missed when using general instruments to estimate...

Economic evaluations conducted to inform healthcare resource allocation often rely on quality-adjusted life years (QALYs) to measure therapeutic benefit. However, QALYs, with underlying health utilities estimated using the EQ-5D or SF-36, may fail to capture the impact of disease for all patients. How well-being and heath utility differ across several common conditions was explored.

This study examined eight diseases: arthritis, asthma, cancer, depression, diabetes, heart disease, lung disease and stroke. Health utilities for each disease were obtained from published literature. Other measures of disease burden, including physical functioning, cognitive functioning and physical activity, were estimated from the National Health and Nutrition Examination Survey (NHANES). Group rankings by these measures were compared to rankings by health utility.

Health utilities were lowest for patients with depression (0.44), and highest for those with cancer (0.81). Physical functioning was most limited (higher score) among those with stroke (28.2) and had the least impact for cancer (24.4). Physical activity was most impacted by heart disease (27.3) and least impacted by depression (40.7). Cognitive functioning was lowest in stroke (41.6) and highest in asthma (52.0).

Differences in rankings of disease severity by metric indicate that the results of cost-utility analyses might be biased against treatments for certain diseases. As patient preferences for clinical outcomes vary, the full burden of disease should be considered in evaluations. Restricting access to treatments based on an incomplete estimate of burden could lead to misallocation of resources and a withholding of therapies that patients find valuable.