The use of quality-adjusted life-years in the economic evaluation of health technologies in Spain: a review of the 1990-2009 literature.

OBJECTIVE: To appraise economic evaluations of health technologies that included quality-adjusted life-years (QALYs) as an outcome measure conducted over the past 20 years in Spain.
METHODS: A systematic review of the literature was conducted. Economic evaluations that included QALYs as an outcome measure, conducted in Spain and published between January 1990 and December 2009 were identified. Primary and gray literature sources were reviewed.
RESULTS: A total of 60 articles and 4 health technology assessment reports were included. Key findings were 1) the vast majority of articles (77.1%) referred to therapeutic interventions; 2) 63.2% dealt with pharmaceutical products and much fewer with preventive strategies, medical devices, or diagnostic interventions; 3) most evaluations referred to cardiovascular- (19.8%), respiratory- (16.3%), and cancer- (13.0%) related processes; 4) 80.3% were based on a theoretical model, most commonly Markov models (71.4%); 5) 67.3% adopted the National Health System perspective; 6) information on the methods used to describe the health states was given in 45.1% of studies; 7) 40.3% used the EuroQoL-5D to elicit preferences, whereas 66.1% gave no details on the methods applied to determine patients' choices; 8) it was possible to state who completed the questionnaires in only 17.7% of studies; 9) 77.1% of the interventions assessed were below the €30,000/QALY suggested affordable threshold in Spain.
CONCLUSIONS: An increasing number of economic evaluations using QALYs had been conducted. Most of them relied on theoretical models. Several methodological issues remain unsolved. Great disparity exists regarding the reporting of the methods used to determine health states and utility values.