Chris Del Mar: 'Tis the season to suspend disbelief

I WAS recently contacted by a Sydney Morning Herald reporter who was trying to understand one miracle of Mary MacKillop that paved the way for her canonisation.

Someone in Victoria prayed to her and a cancer declared hopeless subsequently went into remission.

What could be the explanation?

It was not hard to talk about possible explanations.

First, the numerator problem; cancers do sometimes remit spontaneously, unexpectedly, the tail end of the normal distribution of survivors of each type of cancer.

And second, the denominator issue; how many people pray to a would-be saint, with most not delivered from a dreadful outcome?

The question itself is interesting because it betrays a human weakness.

We are prone to overemphasise associations and believe them to be causal.

A person with cancer prays to a dead nun and gets better.

Intuition suggests it was the act of piety, right?

Astonishingly the story caught on and propagated through media channels.

The telephone rang for interviews.

Worse, the two-dimensional simplification of poorly informed journalists reduced the story down to Catholic vs anti-Catholic.

Not just anti-Catholic, I was being pushed into the corner of criticising all churches, all religions.

Impertinent (and irrelevant) questions followed.

Was I a Christian?

Did I believe in God?

My atheism was the focus of comment on a Catholic website.

So, why the wrong question?

Unlike Richard Dawkins, I don’t see science and mathematics as a bulwark against religion, something to be stamped out.

Rather, let’s marvel at the way scientists (including, of course, clinicians) are able to cope with the dissonance of having religious beliefs (for example, that there is a magic and mystic component to life) completely at odds with their scientific ones (the machinery of DNA can explain how this works) without any grating of sensibility.

Within this context, it is interesting to speculate how religion actually evolved, as we must presume it did.

This is not to say that religion cannot be intrusive to the delivery, and education, especially of science.

The debates in America about whether Darwinian evolution by natural selection should be taught in schools alongside creationist theories seem to be anachronistic by about 150 years.

But, in general, religion and science get along just fine.

Rather, the question we should be brooding over is how we can be more rational when it comes to addressing the distressing business of over-associating phenomena, particularly when it comes to treatment effects that can be turned into “miracles”.

This is very important in medicine; together with many other things, patients (and, all too often, their doctors) fail to appreciate such as the placebo effect and regression to the mean.

As an illustration, I remember as a very young GP counselling a patient with high cholesterol after screening.

He ate a hearty high-fat diet.

Could he cut down on the steak and eggs and bacon? And come back in 6 months with a new lipid screen?

When he did return, he showed a huge reduction.

I beamed at him at the follow-up visit: “Well done. Whatever you’ve changed in your lifestyle is working well!”

“Well, Doc,” he replied, “I ain’t changed an effing thing” ― except he didn’t say “effing”.

It was a decade before I appreciated the regression-to-the mean effect when two measures are imperfectly correlated.

Our job is to make sure we don’t fail to manage the interpretation of data as badly as our more credulous patients.

This matters.

Patients with poor health literacy have poorer health outcomes, which may be causal.

Which may mean we need more than a passing acquaintance with statistics and epidemiology, something we too often bungle, to explain “miracles”.

If we don’t really understand these effects, what hope is there for our patients?

Professor Chris Del Mar is Professor of Primary Care Research, Bond University, Queensland.

Posted 13 December 2010