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Guiding our way through medical guidelines

Staying abreast of all of the latest medical guidelines can be a tough gig for many busy primary care professionals. Dr Simon Cowap speaks on guiding his way through all of the guides available, and extracts his most important findings from the latest heart failure guidelines release.

 

One of the major changes since I started in medicine 30 years ago has been the explosion of guidelines. Back in the day you might have been lucky enough to have the odd handbook for guidance. I remember a very battered soft cover paediatric handbook that went everywhere with me and saved my – and more importantly some poor child’s – bacon on many occasions. But most of the time you were restricted to your own meagre store of knowledge, any colleague you could get hold of and a few ancient textbooks.

The push for evidence-based medicine (not that we entirely made it up as we went along even in the dark ages of the 1980s) combined with the IT revolution has of course led to a profound change in expectations of how current our knowledge should be. At the same time, there has been a vast increase in the volume of scientific output. As measured by published papers, some estimates have this doubling every nine years since 1950.  In medicine alone, 806,000 papers were indexed by MEDLINE in 2015. Allowing half an hour per paper, it would take over 40 years of nonstop reading to get through them all.

Hence the need for some digestive process! This has mostly taken the form of various expert bodies sitting down and distilling key research in their own area into some usable content. The complexity of hundreds of scientific papers is reduced to the simplicity of an algorithm, all instantly available via your web browser. It’s estimated that over 80% of the medical curriculum has at least one relevant guideline. From Aboriginal and Torres Strait Islander health to X-rays (well radiology & imaging anyway), there’s a guideline for just about everything. For those not familiar with it, www.imagingpathways.health.wa.gov.au is in fact one of my favourite set of guidelines. And of course, apart from all the individual institutions that publish guidelines relevant to their own specialty areas, Therapeutic Guidelines came to the party fairly early and now cover a wide range of topics.

By and large, it’s been an enormously useful development and it’s almost impossible to imagine practicing without access to these resources. There are some caveats. Guidelines usually rely on studies that have strict exclusion criteria, often excluding the elderly or those with multiple morbidity, so may not always reflect the reflect the patients they actually get used on. And there has been a concern they can be followed too slavishly, create dependence and result in a loss of clinical decision-making skill. I think there is something in this, but on the other hand someone prepared to abrogate their own clinical decision making to an algorithm was probably never going to be a very good doctor. However, it is essential to remember that guidelines are there to support and inform practice, not dictate it. Every treatment decision remains an individual decision determined by a range of circumstances unique to that patient. We must feel perfectly free to do things ‘outside the guidelines’ so long as we have a cogent clinical reason.

As usual, a number of clinical guidelines were published this year. The National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand were particularly busy, putting out updated guidelines on both atrial fibrillation and heart failure (following on from recently updated European and American heart failure guidelines).

The heart failure guidelines were a great example of how useful these things are in getting new developments across to general practice. For one thing, they made clear to me the role of BNP in diagnosis, something I’d always been uncertain about. They also cleared up confusion about the grey zone of ejection fractions between 40 & 50% - this is now clearly defined as HFrEF. In terms of management, it was a case of something old and something new. As most of us are used to, unless contraindicated, we should get HFrEF patients on to ACEI or ARB, mineralocorticoid receptor antagonist and B blocker.

What’s new, though, is for patients on maximal tolerated doses of conventional therapy whose ejection fraction is still ≤40%, we can switch from ACEI/ARB to something called an ARNI – angiotensin receptor neprilysin inhibitor. This is a brand-new class of agent (the neprilysin inhibitor part anyway) that prevents breakdown of BNP and so increases its useful effects in heart failure. There’s good evidence that this switch can further reduce mortality in our heart failure patients. And while many of us will refer our heart failure patients to cardiologists or heart failure services at some time, for many of us these guidelines will give us confidence to start prescribing something new.

Just as ACEI and heart failure B blockers were specialist-only medications to begin with, over time GPs will become much more likely to initiate ARNIs too.

Keep those guidelines rolling in 2019!

 

Keen to get up to date with the latest heart failure guidelines too? Click here for an easily digestible summary of how how GPs should diagnose, classify and manage HF, or here to access our range of free and accredited HF activities. 

 

Simon Cowap

Dr Simon Cowap MBBS (Hons), FRACGP
Simon is something of an accidental GP who likes to pretend he’s an artist trapped in a professional’s body. He dropped out of his first degree (arts) and went to London to play bass guitar in a band too musically challenged even for punks. Dropping back in to university, he subsequently also failed to complete a science degree and a Masters of philosophy. His remarkable lack of artistic success has been continued by the non-publication of his several novels. Somewhere along the line he did finish a medical degree. He still harbours dreams of literary success but his family have forbidden him to give up the day job.