Ethics and evidence-based medicine.

Concerns about the ethics of evidence-based medicine (EBM) relate to possible alterations in the humane basis of clinical care. In collecting the evidence for EBM, scientists and doctors, not consumers, determine research objectives, interpret the data and implement the findings, and in doing so may disregard patients' priorities. Ethical standards, and what counts as evidence, are determined by socially or commercially powerful groups connected to powerful institutions. Such groups can generate evidence and determine "gold standard" knowledge, filtering out other, "inferior" knowledge. Applying the available evidence to predicting outcomes for individual patients involves uncertainty. Full disclosure of this uncertainty is a component of informed consent, but requires sensitivity to patients' tolerance of ambiguity. Ongoing debate about the ethics of EBM on all levels will ensure that EBM manifests intended and preferred social values and takes its rightful place in the practice of medicine and the development of health policy.