Are the best available clinical effectiveness data used in economic evaluations of drug therapies?
OBJECTIVES: Use of evidence on clinical effectiveness that is of poor quality or is biased in favour of the therapy under study is a concern in economic evaluations and may contribute to a mistrust of pharmacoeconomic studies. This study aimed to determine whether the authors of economic evaluations use the best available evidence for clinical effectiveness. METHODS: One hundred economic evaluations of drug therapies (published in 2001-2003) were sampled randomly from the National Health Service Economic Evaluation Database, and the source of clinical evidence was identified. For each therapy, alternative, high quality sources of clinical effectiveness data were sought by searching the Database of Abstracts of Reviews of Effects and Health Technology Assessment databases. The magnitude and direction of the effect size in the different sources of evidence were compared. RESULTS: Relevant systematic reviews were found for only 32 of the 100 economic evaluations in the sample. In three ca
