Effect of health-related quality-of-life instrument and quality-adjusted life year calculation method on the number of life years gained in the critical care setting.

Objectives: Health-related quality of life (HRQoL) and quality-adjusted life-years (QALYs) gained are basic elements in the cost-utility evaluations of health care. Different HRQoL instruments produce different scores for the same patient, and thus also a different number of QALYs. We examined the effect of these factors on the number of QALYs gained and the cost per QALY in the critical care setting.

Methods: In 937 patients having been treated in the critical care setting in the Helsinki University Central Hospital the HRQoL scores were measured by the EQ-5D and 15D 6 and 12 months after start of treatment, and QALYs were calculated using four different sets of assumptions regarding recovery from disease.

Results: The mean number of QALYs gained during the first year after treatment ranged from 0.178 ± 0.206 to 0.550 ± 0.508 and the consequent cost per QALY from €38,405 to €118,668 depending on HRQoL instrument and assumptions used in the calculations regarding recovery from disease.

Conclusions: The HRQoL instrument and the assumptions employed regarding recovery from disease have a great influence on the results of cost-utility analyses and should, therefore, be explicitly described in studies reporting QALYs. Furthermore, a common consensus on which calculation method should be used within critical care would be urgently needed.