Physiological mechanisms and epidemiological research.

In evidence-based medicine's hierarchy of evidence, physiological research ranks very low. Recent work in philosophy of science has suggested that there may be a role for knowledge of physiological mechanisms in clinical decision making, either (in some rare circumstances) by providing sufficient evidence that a therapy is effective or by bridging the gap between the results of clinical research and the care of individual patients. I argue that both suggestions are problematic and suggest an alternative role for physiological research. Specifically, I suggest that knowledge of physiological mechanisms should be better incorporated into the kind of epidemiological research that is central to evidence-based medicine.