Sue Ieraci: The burden of scientific proof

WE are living in a postmodernist world: everyone’s opinion is valid and every discussion must include “balance”.

The community has a tendency to see medical practitioners as arrogant and narrow-minded, unaccepting of the other healing modalities that are so popular with Australians.

When we speak out about non-evidence-based therapies from other disciplines, we are reminded about glass houses.

This makes me ponder two questions: first, how much of our mainstream medical practice is truly evidence-based; and second, how open should we be to the unexplained?

Many people think that evidence-based practice is restricted to those therapies that are supported by randomised controlled trials.

That’s not always the case, though.

Some therapies are science-based because they hold scientific validity.

We know, for example, that draining a pneumothorax works anatomically and physiologically — there is no reason to test it experimentally.

In the same way, physics supports the use of a parachute when jumping from a plane.

We have physiological models for everything from diuretics and proton-pump inhibitors to bone grafts and coronary grafts.

Clinical trials of efficacy and safety build on this knowledge.
    
In my view, the initial test of scientific validity — or even feasibility — is a crucial one.

We have no physiological model for acupuncture — though there is evidence that it can modify pain perception.

We have a good understanding of the anatomy and physiology of nerve transmission, neurotransmitter secretion and hormone receptors, which do not explain the traditional chiropractic theories of “subluxation” affecting organ function.

We know that the dilutions involved in homeopathy, which can result in no single molecule of the active ingredient being present in the “remedy”, can have no physiological action.

And yet, these and other physiologically implausible modalities are said to “work”.

So — to what degree should medical practitioners be open to modalities that are not explained by our understanding of the human body?

We know that knowledge accumulates gradually — there is rarely a complete revolution.

Now that we can directly image the body by electron microscopy and functional magnetic resonance imaging, it seems unlikely that the clinical sciences will be turned upside-down — more likely, they will continue to be refined.

The Australasian Integrative Medicine Association refers to the “blending of conventional and natural/complementary medicines and/or therapies along with lifestyle interventions ... with the aim of using the most appropriate, safe and evidence-based modality(ies) available”. 

We know that chiropractic manipulation is as effective as a number of mainstream practices for patients with musculoskeletal back pain.

We know that massage, relaxation and meditation can have positive effects on wellbeing, particularly in chronic illness.

We also know, however, that some medical practitioners embrace modalities that go beyond both feasibility and evidence — be it super-doses of supplements or even invasive therapies like chelation.

Should registered practitioners only “integrate” therapies for which there is both scientific validity and therapeutic effect shown, as well as safety?

And if a therapy is feasible, effective and safe, shouldn’t it become mainstream?

 

Dr Sue Ieraci is a specialist emergency physician with 30 years’ experience in the public hospital system. Her particular interests include policy development and health system design, and she has held roles in medical regulation and management.