Monday, April 24, 2006

The thrust and parry of the evidence-based-medicine debate

The debate around evidence-based medicine (EBM) makes for fascinating reading, not least because of the prevalence of hyperbole. In a 2004 paper (it's not open access, but here is the reference), Massimo Porta writes:
"Common sense should build upon a body of evidence and experience accrued over the centuries and shared by the medical community. That some members of the community have made it their task to define which parts of the collective experience constitute evidence and which have less title to reach above water has contributed to the current state of affairs. EBM acolytes now perceive practitioners as grubby underlings, hopeless at applying the latest (evidence-based) literature. Clinicians, resentfully, feel watched by nerds who spend their time sipping coffee while talking to computers instead of patients."
Ow! He continues:
"When it began, it all sounded rather sensible: treatments should be tested for efficacy and trials should be controlled, randomized, double-masked and sufficiently powered. Procedures that do not pass muster should not be recommended for use in clinical practice and self-respecting, commonsensical doctors should refrain from adopting them anyway. But then epidemiologists, statisticians and librarians saw power befalling them as they trotted unexplored avenues towards number crunching."
Given my recent post, I was rather amused by his references to power-hungry number crunchers! In part he was responding to a tongue-in-cheek article in the 2002 holiday issue of BMJ, which purports to reveal the 10 commandments of evidence based medicine:
  • Thou shalt treat all patients according to the EBM cookbook, without concern for local circumstances, patients' preferences, or clinical judgment
  • Thou shalt honour thy computerised evidence based decision support software, humbly entering the information that it requires and faithfully adhering to its commands
  • Thou shalt put heathen basic scientists to the rack until they repent and promise henceforth to randomise all mice, materials, and molecules in their experiments
  • Thou shalt neither publish nor read any case reports, and punish those who blaspheme by uttering personal experiences
  • Thou shalt banish the unbelievers who partake in qualitative research, and force them to live among basic scientists and other heathens
  • Thou shalt defrock any clinician found treating a patient without reference to all research published more than 45 minutes before a consultation
  • Thou shalt reward with a bounty any medical student who denounces specialists who use expressions such as "in my experience"
  • Thou shalt ensure that all patients are seen by research librarians, and that physicians are assigned to handsearching ancient medical journals
  • Thou shalt force to take mandatory retirement all clinical experts within a maximum of 10 days of their being declared experts
  • Thou shalt outlaw contraception to ensure that there are adequate numbers of patients to randomise.
The humour and inflated language aside, there are some big issues here. For example, is it appropriate to hold up the randomized controlled trial (RCT) as the "gold standard of evidence" and relegate basic science to an inferior position? The authors of a philosophical analysis of the evidence-based medicine debate argue that:
"Statistical information from an RCT is virtually uninterpretable and meaningless if stripped away from the backdrop of our basic understanding of physiology and biochemistry."
Compare this with what one of the originators of evidence-based medicine has to say:
"In many [cases], empirical solutions, tested by applied research methods, are "holding the fort" until basic understanding—of mechanisms and interventions—is forthcoming."
This is just a small sampling. The debate about evidence-based medicine and more generally the evidence-based movement is huge. And with good reason: there's an awful lot at stake.
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