Measuring QALY gains in practice: A review of 315 published CEA/CUA in 2010

Objective
Based on a review of all cost-effectiveness (CEA) and cost-utility (CUA) analyses published in 2010 that had measured health outcomes in terms of quality adjusted life years (QALYs) gained, we aim to contribute to improved knowledge on how QALYs are being measured in practice.

Methods
We searched the database EMBASE using Emtree terms and text words specific to economic evaluation and preference based QALY instruments. The search was for convenience limited to the year 2010. 575 studies were identified. Two reviewers went through the identified titles and excluded studies based on predefined criteria. The key inclusion criteria in the review process were that papers should be published in peer-reviewed English language journals, and report from an applied study. After exclusion, data was extracted from 315 studies.

Results
The studies were published in three types of journals; clinical or medical specialty journals (58%), non-specialty medical and health journals (16%), and health economics type journals (26%).  Most studies had their origin in North America and Europe: US (28%), UK (23%), Canada (9%), Netherlands (8%), more than one country (4%), and rest of the world (28%). About half the studies (52%) were pharmaceutical interventions.
 
In 61% of studies there was no reference to which generic descriptive system had formed the basis for measuring health related quality of life (HRQL).  Among the studies that explicitly referred to the use of a generic descriptive instrument (or a multi attribute utility instrument), the EQ-5D was the most frequently used (75/100). See Table 1.
 
 The valuation method used for calculating HRQL was reported in only 70 publications, of which TTO was the most widely used method (43). The majority of studies (60%) had used active comparator, and thus reported the incremental QALY-gains. In 35 of the 315 studies included, the incremental QALY gain was not reported. The magnitudes of the gains were small, with a median gain of 0.06 QALYs, Table 2. The most commonly used discount rate was 3%, Table 3.

Conclusion
This comprehensive review of recently published CUA reveals that the assumptions and methodologies underlying the QALY calculations are not reported in a sufficiently transparent way. EQ-5D is by far the most widely used instrument for measuring health related quality of life. The majority of calculated QALY gains appear to be small.