Debate: Should GPs use NICE’s approach to diagnose asthma?
Two GPs debate
Dr John Ashcroft: GPs need the tools to do this properly
Asthma is not my main area of interest, and I certainly wouldn’t call myself an expert, more a ‘jobbing GP’ – which is perhaps why I would like to see better availability of ‘objective’ tests to help diagnose asthma.
I welcomed the move from NICE to recommend routine use of spirometry and FeNO testing to confirm a diagnosis, despite the outcry from many in our profession. Spirometry has been available for some time but is underused, while FeNO measurement will, for me, offer the most significant enhancement to our approach.
My experience has shown me that diagnosing asthma properly is not as easy as it first appears, and the evidence suggests that this is not just down to my inadequacies as a GP, or my UK GP colleagues, or doctors in general.
A study from the Netherlands in early 2016 – which received a lot of media attention, coming just a few months after NICE published its draft guidance in September 2015 – indicated that maybe over half of children diagnosed with asthma didn’t have it. It wasn’t the only study to show this, and the problem is not confined to children; another study found 30% of adults with asthma had been wrongly diagnosed.
Too many think general practice is not worthy of spending NHS coffers on
A misdiagnosis of asthma can have a major impact on patient’s lives, potentially preventing them from entering certain occupations such as the army or air force unnecessarily, and of course also leads to over prescribing. The cost of asthma treatment is estimated to be at least £666 million a year in the UK, most of which is down to spending on inhaled steroids.
Yet we know only certain patients benefit from these drugs. Becotide – beclometasone dipropionate, the original inhaled steroid – almost never made it to market as the first trials of it in the late 1960s failed to find any benefit. I had the privilege of knowing Dr Harry Morrow-Brown, arguably the expert who ‘saved Becotide’. He showed that only patients with eosinophiles in their responded to oral steroids, and then famously to Becotide.
However, we have never been able to routinely test sputum for eosinophils, so in effect we have been handing out inhalers to patients in much the same way they were given to patients in those initial failed clinical trials.
Fortunately we now have FeNO testing as an indirect measure and the machines these days are small, simple to use and relatively cheap. Some claim the evidence for FeNO testing is lacking; I do not believe the problem is with the evidence, but that too many in positions of power in the NHS, and that includes a few GPs, do not think general practice is worthy of spending NHS coffers on. This extends to a whole host of investigations that should be available to GPs, many approved by NICE, such as Cystatin C to better diagnose kidney failure, B-type natriuretic peptide for heart failure and near-patient C-reactive protein testing for sepsis and pneumonia.
GPs should stop making do, and start demanding the tools to let them do their job properly.
Dr John Ashcroft is a GP in Derbyshire
Dr Duncan Keeley: Proper follow-up is what’s needed
GPs have conflicting guideline advice on asthma diagnosis. Should we use the NICE diagnostic algorithm? No. Should we use objective testing to support a diagnosis of asthma – yes, whenever possible. I will explain.
An asthma diagnosis needs to be made carefully. Three things can go wrong. People can receive an asthma label without having asthma at all, most commonly children with self-limiting viral associated wheeze. People can have asthma without the diagnosis being made. And people with other diagnoses can be incorrectly diagnosed as having asthma.
How do we go wrong? By far the most common reason lies in failures in basic clinical method. Asthma diagnosis rests mainly on careful history taking, examination, follow-up and diagnostic review by a well-trained clinician. This is especially true in young children for whom all objective tests are difficult or impossible. Good education and training of health professionals is vital, along with adequate time with the patient and – preferably – continuity of care. With the current pressures on primary care all of these are compromised. Guidelines can say what they like, but mistakes will be made more often if the basic clinical job is not done properly.
GPs feel under pressure to make diagnoses and pass asthma care to nurses, but not all GPs are confident in asthma diagnosis and not all nurses have received the necessary training in respiratory care to make and to question asthma diagnoses.
Peak flow monitoring is the best first line objective test
Objective testing should be used wherever possible, but the NICE algorithm has the tests in the wrong order. Peak flow monitoring is the best first line objective test. It is universally available, easily repeated and has a high specificity – an excellent test for ruling in asthma. A period of peak flow monitoring should be started as soon as an asthma diagnosis is suspected, especially if the symptoms warrant an immediate trial of therapy. Like all the other tests, though, it requires training to do properly, it is fallible, and the results require interpretation in the light of the whole clinical picture.
Spirometry with reversibility is advocated rather than peak flow monitoring in the NICE guidelines, but this only gives information at a single timepoint, and is often normal by the time the test can be done. Also, for various reasons, the standard of spirometry in primary care is often suboptimal.
FeNO testing is the most controversial addition to the recommendations in the NICE guideline. Opinion in the respiratory community is divided as to its value. The international GINA (Global Initiative for Asthma) guidance says it has no useful role, the BTS/SIGN (British Thoracic Society/Scottish Intercollegiate Guidelines Network) list it as an alternative additional objective test, whereas NICE makes FeNO testing central to asthma diagnosis.
Moreover, only two thirds of hospital trusts and very few general practices offer FeNO testing. The NICE guideline acknowledges that this poses problems for implementation and recommends following the BTS/SIGN approach until its recommended tests are more widely available.
We will gradually learn whether FeNO and spirometry offer sufficient additional value to warrant the costs of provision, and this may be explored by trial provision through community based diagnostic hubs. But resources for additional services are currently hard to find.
What should we do in the meantime? The Primary Care Respiratory Society UK has produced a useful consensus advice document, which essentially outlines how and why GPs should follow the BTS/SIGN approach rather than NICE.
Dr Duncan Keeley is Executive Committee policy lead for the Primary Care Reparatory Society UK. This response is submitted in a personal capacity.
1. Looijmans-van den Ekker I et al. Overdiagnosis of asthma in children in primary care: a retrospective analysis. Br J Gen Pract 2016; 66: e152-e157
2. Luks VP et al. Confirmation of asthma in an era of misdiagnosis. Eur Respir J 2010; 36: 255-260
3. Asthma UK - press release.
4. Morrow-Brown, H. The Becotide story. Allergies explained blog
5. Primary Care Respiratory Society UK. Asthma guidelines briefing document (2017).