title: [How are quality-adjusted life years defined in German studies?].
abstract: OBJECTIVE
  Cost-utility analysis, a way of evaluating health-economic data, is of increasing importance in Germany. It was the aim of this study to provide a systematic survey of all published cost-utility studies on the German health system. In addition to collecting general study characteristics, particular attention was paid to three questions: (1) On what populations are the utility values based that are necessary for calculating quality-adjusted life years (QALYs); (2) by what method were the data generated; and (3) how was the construction of the health-related results documented?
  
  
  METHODS
  In the course of systematically reviewing all German health-economic evaluations, cost-utility studies published between 1990 and 2004 were identified. For this purpose both generic and specific health-economic databanks were searched using clearly defined criteria. The fulfillment of explicit criteria for inclusion and exclusion were tested and relevant items of information extracted from the full text.
  
  
  RESULTS
  Among 730 studies for which the full text was analysed 18 cost-utility studies were identified. Most of them were in medical journals in English and their objective was to evaluate curative medical interventions. The methods used for generating utility values differed greatly between them and in general were inadequately documented.
  
  
  CONCLUSIONS
  Most cost-utility studies combine utility values that were generated from different perspectives and countries of origin. In addition they used different methods of assessment. As a rule the methods for determining utility values were not transparent and inadequately documented. The calculations of QALYs based on these studies are not comparable. Most of the studies cannot be assumed to reflect the utility of medical care in respect to German patients or the German population.
authors.affiliation: Universität Witten-Herdecke, Witten. Davids@uni-wh.de
authors.forename: D L
authors.initials: DL
authors.lastname: Schwappach
authors.forename: T A
authors.initials: TA
authors.lastname: Boluarte
mesh_terms: D003362:Cost-Benefit Analysis; D005858:Germany; D006304:Health Status; D006801:Humans; D019057:Quality-Adjusted Life Years; D015203:Reproducibility of Results; D026712:Value of Life