EVIDENCE-based medicine is one of the mantras of our times, but does it always live up to its promise?
Few doctors would challenge the need for evidence-based medicine (EBM) to support clinical interventions, particularly ones that carry risks. The commitment to evidence-based practice is, after all, what distinguishes medicine from some of the less soundly based alternative health offerings (but let’s not talk about homeopathy …).
In recent times, though, there have been a number of criticisms from within mainstream medicine of what some dub “brand EBM”.
Among other things, the EBM movement has been attacked for being anti-industry, pro-industry, fundamentalist, reductionist, overly linear, masculinist, lacking in self-criticism and intellectually dishonest.
Australian expatriate science communicator Hilda Bastian is the editor of PubMed Health and a founding member of that lynchpin of EBM, the Cochrane Collaboration, but she’s also something of a critic.
As she wrote in a blog last week, despite being “enthusiastic about evidence”, she is concerned the EBM movement has become “very attractive to people with a barrow to push”.
One of the movement’s successes has been the rise of the systematic review and meta-analysis, she writes, but she also cautions about the limitations of reviews that may be out-of-date before they are published and are not always as objective as people might think.
The fact that different reviews reach conflicting conclusions about the same body of evidence indicates there is “plenty of room” for people to reach a “desired conclusion”, she writes.
In an earlier Scientific American blog, she outlined some of the conflicting statements about risks and benefits made in reviews of mammography screening, for example.
Queensland GP Dr Pamela Douglas is another who has raised concerns about the limitations of EBM, especially when applied to the complex world of general practice.
Widespread diagnosis and medication of gastro-oesophageal reflux disease (GORD) in unsettled infants was, she argued in a 2011 article for Griffith Review, an example of EBM gone wrong.
“The GORD epidemic is best framed as a by-product of reductionism in medical research, the same reductionism that proved fertile ground for the rise of brand EBM”, she wrote.
Reductionism might be a useful tool in highly specialised, hospital-based research but on its own “fails to make sense of the breathtakingly complex, stunningly unpredictable, constantly dynamic problems that a GP in the community encounters in her consulting room every day”, she wrote.
“So what do you do when you are confronted by an expectation that you practise according to the ‘evidence’ — an agreed clinical protocol written up in authoritative peer-reviewed journals — when the evidence contradicts what you have reason to believe, from your own transdisciplinary knowledge base, is in your patient’s best interests?” she asked.
The widespread diagnosis of infant GORD and recommendations for treatment resulted from a narrow approach that ignored research in other disciplines and included a number of unquestioned assumptions, she wrote, including that a clinical sign (in this case, a crying baby) must be the result of disease.
The surge in prescribing of proton pump inhibitors to babies that resulted may have put them at increased risk of developing food allergies, she suggested.
But if GORD was being overdiagnosed — and overtreated — in babies, as Dr Douglas believes, would that represent a failure of the principle of EBM, or perhaps more a failure to properly implement it in a clinical setting?
An essay published in The BMJ last year identified a number of problems with current models of EBM, including the ability for vested interests to manipulate the process, the unmanageable volume of evidence available on some topics, overstatement of benefit in much published research, lack of attention to the role of comorbidities, and an overemphasis on algorithms rather than the individual patient.
But throwing out the EBM approach was not the answer, these authors wrote, arguing the increased focus it had brought to systematic collation, synthesis and application of high-quality evidence had saved lives.
Instead, they called for a new commitment to “real evidence-based medicine”, a return to the movement’s founding principles: “to individualise evidence and share decisions through meaningful conversations in the context of a humanistic and professional clinician-patient relationship”.
Jane McCredie is a Sydney-based science and medicine writer.