Evidence-based medicine in theory and practice: epistemological and normative issues

Evidence-based medicine (EBM) emerged during the 1990s, with the aim of improving clinical practice by increasing the extent to which clinical care was informed by medical research, particularly randomized controlled trials (RCTs) and systematic reviews of RCTs. This chapter gives an account of EBM, followed by examination of epistemological and ethical justifications and critiques of EBM. EBM relies upon epistemological claims about the ability of RCTs to eliminate certain forms of bias and to establish whether or not there is a causal relationship between an intervention and an outcome. However, epistemological critiques of EBM include reservations about whether EBM can “prove” causation, concerns about the rejection of mechanistic models of causation, challenges associated with applying the results of RCTs to individual patients, and lack of evidence regarding whether EBM has in fact benefitted patients and healthcare systems. The ethical justifications for EBM include its promise of better patient outcomes through better informed clinicians and the idea that public health policy based on EBM can support equity and minimize waste of resources. Ethical critiques of EBM note that despite its potential for reducing particular forms of bias, the research upon which EBM is based is often industry funded, creating conflicts of interest that are associated with new sources of bias. These include bias in the conduct of trials, the publication of results, and the choice of interventions for investigation. EBM also poses challenges for patient and clinician autonomy, especially where evidence-based clinical practice guidelines are enforced through targets or audits. In the face of these concerns, EBM is under pressure to reestablish its credibility. The chapter ends by identifying three current initiatives that seek to reinstate the aims of EBM to better inform healthcare decisions.