QUALITY-ADJUSTED LIFE-YEARS FOR THE ESTIMATION OF EFFECTIVENESS OF SCREENING PROGRAMS: A SYSTEMATIC LITERATURE REVIEW

Objectives: The aim of this study was to identify and characterize studies that have used quality-adjusted life-years (QALYs) based on measurements of patients' health-related quality of life (HRQoL) as an indicator of effectiveness of screening programs. Methods: Systematic search of the literature until March 2010, using several electronic databases. Initial screening of articles based on abstracts, and evaluation of full-text articles were done by at least two of the authors. Results: The search identified 1,610 articles. Based on review of abstracts, 431 full-text articles were obtained for closer inspection and, of these, 81 reported QALYs based on patient-derived data using a valid HRQoL assessment. The most frequently used method to assess HRQoL was Time Trade-Off (55 percent) followed by EQ-5D (26 percent). The most frequently studied medical conditions were malignant diseases (23 percent) followed by cardiovascular diseases (19 percent). All studies employed some kind of modeling with the Markov model being the most prevalent type (65 percent). Majority of the articles (59 percent) concluded that the screening program studied was cost-effective. Conclusions: The use of QALYs in the evaluation of screening programs has expanded during the last few years. However, only a minority of studies have used HRQoL data derived from patients, using direct or indirect valuation. Further investigation and harmonization of the methodology in evaluation of screening programs is needed to ensure better comparability across different screening programs.