What constitutes evidence in hospital new drug decision making?

In National Health Service hospitals in the UK the introduction of new drugs is controlled by a local Drug and Therapeutics Committee (DTC), which is expected to apply the principles of evidence-based medicine (EBM). In the light of growing expenditure on drugs, there is interest in how the decisions are made that lead to the local acceptance or rejection of a new drug. In this study the DTCs of two general hospitals were observed, tape-recorded and analysed to determine what was considered as evidence and how it was used in decision making. Evidence, as constituted by DTC members, was issues that affected the decision-making process and included: clinical trial data, cost, pre-existing prescribing of the drug, pharmaceutical company activities, decisions of other DTCs, patient demand, clinician excitement, and personality of the applicant. Debate usually started with a discussion of the scientific evidence, then the cost would be considered. Often this evidence was either inadequate or insufficient enough for a locally implementable decision and further types of evidence would be brought in to try and estimate the likely impact of adopting the new drug. EBM, while used in decision making, was supplemented by local knowledge, although decisions were accounted for in the language of scientific rationality. Both abstract scientific rationality and the local rationality of practical healthcare provision were present in the decisions of the DTCs on the adoption, or otherwise, of new drugs into local formularies and healthcare. We suggest the coming together of local and abstract in local decision-making needs to be taken into account when formulating policy and providing decision support.