Monitoring treatment

by Dr Norman Swan

The practice of monitoring a medication's effectiveness is being questioned after recent research findings.

24 08 2009

Sometimes research findings turn medical practice on its head. And that's happened recently. The practice in question is checking whether a medication's worked, by doing follow-up tests like blood pressure or the density of your bones.

What could be more sensible and reassuring if you're on pills for high blood pressure or osteoporosis tablets? Well, groundbreaking Australian research is suggesting that treatment monitoring may actually mislead both doctor and patient, and potentially lead to harmful decisions.

It's a long story, but I've only got a minute so I'll cut it short. When tests are repeated they can vary quite a lot for a lot of reasons, which have nothing to do with what's really going on inside your body. The researchers looked at this test variation in blood pressure and osteoporosis drug trials, and found that when you allowed for the variability, far more people were helped than the trials actually indicated. People who were thought to be non responders, weren't in fact, when you removed the noise from the testing. Everyone – at least who took these particular drugs – improved. The risk in doctors monitoring patients, is that if the test shows no effect they might be tempted – wrongly – to stop the treatment, when in reality the medication has worked.

If this is true, then millions of dollars are potentially being wasted each year and some harmful choices being made. Medical authorities are going to have to fund more of this kind of research to work out how doctors should change what they've long been taught to do – and what we've come to expect of them.