Asthma deaths are increasing, despite a plethora of published evidence and guidelines. From a low of 997 deaths in England and Wales in 2009, the number rose to 1392 in 2018 (Office for National Statistics, 2020). In the UK, three people die of asthma every day (Asthma UK, 2018).
The National Review of Asthma Deaths (NRAD) found that there was a lack of health professional knowledge of the UK guidelines in 25% of asthma deaths reviewed. The expert NRAD panels identified factors that could have avoided death in relation to the health professional's implementation of asthma guidelines in 46% of cases, with a specific lack of asthma expertise in 17% of cases (Royal College of Physicians (RCP), 2014). Although it has been alleged that only one of the 19 recommendations from this report have been currently implemented (Levy, 2018), various national initiatives have been taken forward, including the inclusion of respiratory disease in The NHS Long Term Plan (NHS England and NHS Improvement, 2019), changes to the Quality Outcomes Framework, the National Asthma Audit, and guidance for asthma from the National Institute for Health and Care Excellence (Asthma UK Centre for Applied Research, 2020).
With two national guidelines and one international guideline providing 729 pages of information from a combined 1914 clinical papers, there is surely a sufficient amount of high-quality evidence available to reduce mortality and improve quality of life (Table 1). It could be that conflicting guidance from three differing sources has created challenges for health provision, and that an opportunity for clarity is urgent and pressing (Keeley and Baxter, 2018).
| Guideline | Number of pages | Number of references |
|---|---|---|
| British Thoracic Society/Scottish Intercollegiate Guideline Network | 207 | 974 |
| National Institute for Health and Care Excellence | 323 | 201 |
| Global Initiative for Asthma | 199 | 739 |
| Total | 729 | 1914 |
The Global Strategy for Asthma Management and Prevention was first published by the Global Initiative for Asthma (GINA) in 2002. This formed an international consensus on the management of asthma, and has been translated into several languages ever since (GINA, 2020).
The British Thoracic Society (BTS) first published asthma guidance in 2003, using rigorous methodology from the Scottish Intercollegiate Guideline Network (SIGN). The BTS/SIGN guidelines have been used as a national reference source in the UK ever since and have been updated every few years, with the last revision made in July 2019 (BTS/SIGN, 2019a).
The BTS/SIGN asthma guidelines remained the sole UK asthma guideline for both primary and secondary care for many years. In 2017, the National Institute for Health and Care Excellence (NICE) commissioned a separate guideline, the aim of which was ‘to determine the most clinical and cost-effective way to effectively diagnose people with asthma and determine the most effective monitoring strategy to ensure optimum asthma control’ (NICE, 2017).
Nurses tend to follow national guidelines more than local guidelines, and there is an ongoing need to improve health professionals' knowledge of asthma guidelines (Booth, 2020). In an attempt to help health professionals navigate the information available, this article compares and contrasts the three guidelines, and signposts nurses to make the best evidence-based decisions for people with asthma. Box 1 includes some common acronyms.
| FeNO | Fractional concentration of exhaled nitric oxide |
| FEV1 | Forced expired volume in 1 second |
| ICS | Inhaled corticosteroid |
| LABA | Long-acting B2 agonist |
| LAMA | Long-acting muscarinic antagonist |
| MART | Maintenance and reliever therapy |
| SABA | Short-acting B2 agonist |
| FVC | Forced vital capacity |
COVID-19
The GINA report of 2020 (GINA, 2020) is the only guideline so far to have published guidance during the pandemic, although both the BTS and NICE have published separate documents on the subject. GINA (2020) advises that patients should continue taking their prescribed medications, especially inhaled steroids, and that they should have a written asthma action plan. Spirometry and peak flow should be avoided in healthcare settings, because these procedures may disseminate the virus. GINA suggests that nebulisers should be avoided where possible because they increase risk of spread, and that a metered dose inhaler (MDI) and spacer should be used instead.
The BTS (2020) COVID-19 advice, although not published within the asthma guideline document itself, is practical and reiterates that treatment strategies have not changed during the pandemic. It is important to ensure that a patient's asthma is as stable as possible, and that people should have a plentiful supply of medication but should not over-order. The BTS COVID-19 guidance suggests that the use of a nebuliser outside hospital is generally not needed, and that for mild to moderate attacks an MDI and spacer can be just as effective. Ten to 12 doses of salbutamol via an MDI and spacer are equivalent to a 5 mg nebule given via a nebuliser. However, for severe asthma attacks where nebulised bronchodilators are required (which should preferably be driven by oxygen, with the monitoring of oxygen saturations), advice from Public Health England (2020) states: ‘Nebulisation is not a VIRAL droplet generating procedure and not considered an aerosol generating procedure for COVID-19.’
Diagnosis
All three guidelines suggest that asthma diagnosis has no gold standard or no single test that can conclusively include (or exclude) an asthma diagnosis. Unlike other long-term conditions such as hypertension or diabetes, asthma has no test that provides an unequivocal numeric value that is completely accurate.
The BTS/SIGN (2019a) guideline provides sensible advice to record ‘asthma suspected’ in the notes of those patients who are currently undergoing a diagnostic workup. NICE (2017) does not provide practical advice such as this; however, it recommends that local areas establish diagnostic hubs to ‘achieve economies of scale’. This approach of centralising diagnosis may be of value to primary care networks.
Asthma diagnosis is largely a clinical one, which should be backed up by objective measurements such as peak flow, spirometry, and reversibility testing. The symptoms of unproductive cough, chest tightness, breathlessness and wheeze (detected through chest auscultation) should vary over time and occur in the presence of identified trigger factors, for example; allergens, cold weather, exercise, respiratory virus or emotion. There are usually two or more of these symptoms present at varying times. A family history of asthma and allergy, occupation, and smoking habits, should complete the clinical picture. This should lead the clinician to consider: ‘I think this patient may/may not have asthma’ (NICE, 2017; BTS/SIGN, 2019a; GINA, 2020).
Detecting variable airflow obstruction
Once the hypothesis has been made that the person may have asthma, objective tests can be undertaken to detect variable airflow obstruction, the presence of which can increase the likelihood of asthma (BTS/SIGN, 2019a).
Asthma is characterised by narrowing of the small airways by constriction of the muscles surrounding them (bronchoconstriction) and inflammation inside them. This narrowing of the airway is known as airway obstruction and occurs in asthma and chronic obstructive pulmonary disease (COPD) among other respiratory diseases (Pavord and Wardlaw, 2010). Narrowing of the airway can be detected by measuring the speed of air coming out of the lungs, through measuring either the peak expiratory flow rate (PEFR) or the forced expired volume in the 1st second (FEV1) via spirometry. When compared with the total volume of air in the lungs that can forcibly be expelled (forced vital capacity or FVC), this provides us with a clinical definition of airway obstruction: where the ratio of FEV1 to FVC is 0.70 or less (BTS/SIGN, 2019a).
NICE (2017) suggests that airway obstruction be defined by an FEV1/FVC ratio that is either <0.70 ‘or below the lower limit of normal if this value is available’. The NICE guideline is pragmatic in that it accepts that the lower limit of normal (LLN) will not always be readily available. It also strongly recommends that spirometry services should be accredited, highlighting the need for training for personnel who perform the test. The BTS/SIGN (2019a) guideline is worded a little more specifically, recommending undertaking ‘quality-assured spirometry using the lower limit of normal to demonstrate airway obstruction’. Both guidelines justify using the LLN, because the FEV1/FVC ratio may be higher in younger people and lower in older people. Using the fixed ratio of 0.70 may therefore underestimate airflow obstruction in younger people and overestimate it in older people.
Although the FEV1/FVC ratio is a defining measurement in COPD, due to the variable nature of asthma an FEV1/FVC ratio less than 0.7 is not always present. In addition, the FEV1 and PEFR can also vary over time, and can increase with suitable treatment such as inhaled bronchodilators or corticosteroids.
All three guidelines acknowledge that variable airflow obstruction is difficult to detect, and more than one visit to the health professional may be needed. This is why the code ‘asthma suspected’ may be useful.
Reversibility
All three guidelines agree that a positive reversibility test can be defined as an increase in FEV1 of 200 ml and 12%, and in children just 12%. BTS/SIGN (2019a) also states that an improvement of 400 ml (without specifying a percentage increase) is also indicative of asthma. The GINA (2020) international guideline attempts to clarify this by stating greater confidence if the increase is >15% and >400ml. There are, therefore, two current definitions of reversibility, either of which are indicative of asthma. All three guidelines suggest that this should be determined only in people who have demonstrated airway obstruction, ie in a FEV1/FVC ratio of 0.7 or less (or below the LLN).
GINA (2020) suggests that, if reversibility testing is negative, then it should be tried again on another occasion. This corresponds with the BTS/SIGN (2019a) advice that a comparison should be made of diagnostic tests undertaken when a patient is asymptomatic with those undertaken when a patient is symptomatic. The aim of this is to detect variation over time. The practicalities of this, however, are difficult, because there may not always be spirometry appointments free when the patient is symptomatic.
A trial of treatment, for example with inhaled corticosteroids (ICS), is a similar process to reversibility, in that the clinical effectiveness of an inhaled therapy is assessed through measuring changes in lung function. The BTS/SIGN (2019a) guidelines suggests that this would typically be a trial of treatment lasting 6–8 weeks and assessed using lung function, as well as a validated symptom questionnaire such as the Asthma Control Test (ACT) (Nathan et al, 2004). An increase of three or more in the ACT is considered to be clinically significant (Schatz et al, 2009).
Detecting airway inflammation
Although spirometry and peak flow measure airflow obstruction, they do not measure inflammation inside the airway. Inflammation, and the treatment of inflammation, is useful to understand when diagnosing and treating asthma.
In recent years, both BTS/SIGN (2019a) and NICE (2017) guidance have recommended the use of fractional concentration of exhaled nitric oxide (FeNO) testing, to detect type 2 airway inflammation, which is associated with higher levels of systemic and airway eosinophilia and positive response to corticosteroids (American Journal of Managed Care, 2019). In the majority of people with asthma, the disease is characterised by eosinophilic inflammation within the airways. The respiratory epithelium produces nitric oxide, which can be detected via a simple breath test: fractional exhaled nitric oxide (FeNO).
The BTS/SIGN (2019a) guideline recommends that FeNO testing be performed on patients who have an intermediate probability of asthma. The guideline recognises that there will be people who also have a high probability and those who have a low probability of asthma, and in these two groups it may be easier to include or exclude an asthma diagnosis (Figure 1).
NICE (2017) suggests FeNO testing for all patients, alongside spirometry with reversibility. The diagnostic algorithm for objective tests for asthma in adults aged 17 years and over (algorithm C, https://tinyurl.com/nice-alg-c) (NICE, 2017) suggests performing spirometry to observe for airways obstruction in the first instance and, then, depending on the results, either conducting reversibility followed by FeNO testing, or FeNO testing followed by home PEFR recording. The guideline is unfortunately contradictory, because on the same page, under ‘Order of tests’, the algorithm suggests that FeNO should be measured first, followed by spirometry and reversibility. This could be suggesting that if FeNO and spirometry are performed at the same appointment, because spirometry is the more strenuous of the two tests, it may be advisable to perform FeNO testing first. However, this is not entirely clear.
The GINA (2020) guidance provides no mention of FeNO testing within its diagnostic algorithm (GINA, 2020). It states that FeNO has not been established for ruling in or ruling out a diagnosis of asthma. It provides justification for this by stating that FeNO levels are raised in eosinophilic inflammation, but also in eosinophilic bronchitis, atopy, allergic rhinitis and eczema. FeNO may also be lower in smokers and raised during infection.
About one in five people with a positive FeNO test will not have asthma (false positives), and about one in five with a negative FeNO test will have asthma (false negatives). This may appear to show the FeNO testing in a negative light. However, this should be compared with reversibility testing, which has been part of national guidelines for many years, and part of previous versions of the quality outcomes framework. Reversibility testing has an even greater range of predictive values. About one in three people with a positive reversibility test will not have asthma, and one in three people with a negative reversibility will have asthma (BTS/SIGN, 2019a).
Because these tests cannot completely include or exclude all asthma diagnosis, the results must be interpreted in the context of a thorough clinical examination and history taking. Diagnosing asthma can therefore be considered to be a jigsaw puzzle of nine pieces, with the various elements of diagnosis fitting together to form a clinical picture (Figure 2).
Pharmacological management
For several years, the BTS/SIGN guidelines have provided a stepwise approach to asthma pharmacology. Previous guidance advised starting with a short-acting B2 agonist (SABA) as required at the first step, then progressing to inhaled corticosteroids (ICS) at the next step, before the addition of a long-acting B2 agonist (LABA) at the third step. This guidance has changed recently, with more emphasis being placed on the commencement of ICS much earlier. BTS/SIGN (2019a) now recommend that everyone with asthma has ICS treatment, with the exception of people with ‘infrequent short-lived wheeze’.
The GINA (2020) guidance states that, for safety, SABA alone cannot be recommended and that all adults and adolescents with asthma should receive ICS. Dispensing more than three canisters of SABA a year is associated with increased emergency department attendance. In addition, GINA (2020) suggests that, when SABA is taken, an extra dose of ICS should be taken at the same time.
The BTS/SIGN (2019a) guidance states that for people who are uncontrolled on ICS, rather than increasing the dose of ICS, a LABA can be added. This should be in a combination inhaler, and can either be used as fixed-dose, or maintenance and reliever therapy (MART) (taking a formoterol-based LABA/ICS combination as both preventer and reliever). After this, the ICS could be increased or the addition of a leukotriene receptor antagonist (LTRA) tablet may be added. Beyond this, treatment must be guided referral to specialist care. At each step, an assessment of control should be made using a validated symptom score, such as the ACT (Nathan et al, 2004), or the RCP's Three Questions (Pinnock et al, 2012), which ask the patient whether in the past month:
Answering ‘no’ to all three is consistent with controlled asthma.
Leukotriene receptor antagonists
The NICE (2017) guidelines follow a similar pattern to the older BTS/SIGN (2019a) guidelines, with commencement of SABA at the first step; then, if there is poor control, the addition of ICS. It is at this next point where the NICE guidelines deviate considerably, by suggesting the addition of an LTRA before LABA. NICE suggests that ICS+LTRA is more cost-effective, although it admits that ICS+LABA is slightly more clinically effective. Twenty-one studies were included in this review undertaken to provide evidence for the NICE guidelines, which is then reported in detail over 48 pages within the guidance.
The limitations to this review of the evidence undertaken for NICE (2017) are that the clinical trials included do not necessarily reflect real-world practice. For example, patients participating in the studies showed a high degree of reversibility to bronchodilators. Some people with asthma do not demonstrate significant reversibility, and therefore may not have been included in the clinical trials reviewed.
In addition, ICS+LTRA was compared against ICS+LABA in separate inhaler devices. There was no apparent review of ICS+LTRA against ICS/LABA in a single inhaler, or against MART. In this respect, the patient could be given a choice between three separate medications—a SABA inhaler, an ICS inhaler, and an LTRA tablet—or alternatively one MART combination inhaler. There may also be safety issues with regard to people who may not adhere fully to their inhaled therapy by taking their LTRA tablet, but not their ICS. However, there may be people who prefer to take a tablet, rather than an additional inhaled therapy.
A systematic review by Chauhan and Ducharme (2014) suggested that there was a higher proportion of patients who preferred ICS+LABA than ICS+LTRA. This review also showed that, in terms of clinical efficacy, ICS+LABA was ‘modestly superior’ to ICS+LTRA.
NICE (2017) agrees that combination inhalers mitigate the safety concerns associated with people taking their LABA inhaler but not their ICS. Because it is not possible to combine LTRA and ICS therapy in one preparation, when considering treatment regimens in the real world, it may be important to consider patient choice, polypharmacology, prescription charges and medication adherence. GINA (2020) emphasises adverse effects with LTRA, including a risk of serious neuropsychiatric events (suicidal thoughts, nightmares and behavioural problems in children).
Maintenance and reliever therapy
The BTS/SIGN (2019a) guidance has recommended MART for some years, placing it as an equal alternative to the traditional SABA as a reliever and ICS+LABA combination as a preventer. NICE (2017) is also broadly supportive of MART, illustrating that it reduces severe exacerbations and hospitalisations, when compared to using SABA as a reliever and ICS/LABA as a preventer.
As required MART
If the recommendation by NICE (2017) of using an LTRA before LABA is considered to be a paradigm shift in asthma management, then the international GINA (2020) guideline may also carry ground-breaking suggestions of its own.
To start with, GINA (2020) agrees more or less with BTS/SIGN (2019a) by recommending that, for safety reasons, treatment of asthma in adults and adolescents should not be with SABA alone. However, GINA (2020) goes a step further by suggesting, in the case of adults, administration of an ICS/LABA combination at the very first step of asthma management. If this is not radical on its own, GINA (2020) recommends that this could be given as required, rather than regularly once a day or twice a day. This can only be given in an ICS/LABA-containing formoterol, due to its rapid onset and dose response. It has also been demonstrated that the ICS budesonide may have a part to play in the rapid onset of clinical effect of this combination (Rabe et al, 2006). It is not clear whether other ICS can be used in the same way.
For children, GINA (2020) suggests that low-dose ICS be taken whenever SABA is taken.
SABA treatment alone does not control airway inflammation and therefore it increases risk of asthma attack. NRAD found that 9% of asthma deaths occurred in people with asthma who were on SABA alone, and that 39% were overusing their SABA medication (RCP, 2014). Taking an ICS at the same time as a reliever treats inflammation immediately, and significantly improves outcomes. This approach to the pharmacological treatment of asthma has been studied many times with Symbicort, which is a budesonide-formoterol formulation given via a Turbohaler (Scicchitano et al, 2004; O'Byrne et al, 2005; Vogelmeier et al, 2005).
The as-required approach to MART comes following the publication of a large study in the New England Journal of Medicine, which looked at the efficacy of Symbicort in mild asthma (O'Byrne et al, 2018). This year-long study of 3836 people with mild asthma aged 12 years and over showed that using budesonide-formoterol as required improved asthma symptom control compared with taking SABA as required. Although not quite as effective as regular twice-daily ICS, as-required MART appears to be a better treatment than relying on a SABA inhaler alone. Three other published studies have demonstrated further support for this approach, which has yet to be licensed for use (Bateman et al, 2018; Beasley et al, 2019; Hardy et al, 2019).
The best of three
Pharmacological advice varies subtly between the three asthma guidelines (Table 2). Each guideline has strong merit, and deciding which approach to take is not easy. NICE (2017) provides a scientific and cost-effective approach, while BTS/SIGN (2019a) offers a more real-world or pragmatic approach to its evidence base. GINA (2020) offers another perspective, looking perhaps to the future by examining strategies that are not yet licensed.
| Treatment step | |||||||
|---|---|---|---|---|---|---|---|
| Guideline | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| British Thoracic Society/Scottish Intercollegiate Network, 2019 | SABA/ICS | SABA+ICS/LABA or MART | SABA+ICS/LABA or MART | Increase ICS or LTRA | Refer to specialist care | ||
| National Institute for Health and Care Excellence, 2017 | SABA | SABA+ICS | SABA+ICS+LTRA | SABA+ICS/LABA+/-LTRA | SABA + ICS/LABA or MART low ICS maintenance | SABA+ICS/LABA or MART moderate ICS maintenance | SABA+ICS/LABA or Seek advice from a healthcare professional with expertise in asthma |
| Global Initiative for Asthma, 2020 | PRN ICS/formoterol* | SABA+ICS low dose or PRN ICS/formoterol* | SABA+ICS/LABA low-dose or MART | SABA +ICS/LABA medium dose or MART | SABA+ICS/LABA high dose or refer for phenotypic assessment | ||
ICS=inhaled corticosteroid; LABA=long-acting B2 agonist; LAMA=long-acting muscarinic antagonist; MART=maintenance and reliever therapy, with budesonide + formoterol or beclomethasone + formoterol; PRN=as required; SABA=short-acting B2 agonist
FeNO testing as part of asthma diagnosis is recommended by NICE (2017) for everyone, by the BTS/SIGN (2019a) for intermediate probability, but it is not recommended at all by GINA (2020).
There has been a call for a conjoined, national guideline, to bring clarity to a therapy area that can be challenging at the best of times (Keeley and Baxter, 2018). A statement issued on the BTS website in July 2019, announced that BTS, SIGN and NICE will issue a joint guideline as ‘part of a broader pathway’ (BTS, 2019b). It may be that the COVID-19 pandemic, the subsequent temporary cessation of lung function testing and the increase in remote/tele consulting has forced a re-examination of available evidence. The draft version of the latest Australian asthma guidelines would suggest a move toward the GINA as-required budesonide/formoterol approach (National Asthma Council Australia, 2020), in which case time may be needed for further consideration. Meanwhile, respiratory interested professionals wait with anticipation.
To support health professionals before this happens, the Primary Care Respiratory Society (PCRS) issued a briefing document that broadly supports the BTS/SIGN diagnostic algorithm, and the use of FeNO testing (PCRS, 2017). However, further evidence is needed to fully understand the usefulness of FeNO testing in primary care. The PCRS also supports NICE in trying LTRA as a first-line add-on therapy to ICS, ‘unless there is good reason to the contrary’. In a further briefing paper published in 2019, the PCRS advised that the decision to use either LABA or LTRA should be made between the clinician and the patient, since both are options (PCRS, 2019).
These briefing papers are welcomed as interim guidance before evidence of the best of two national guidelines (and perhaps an international guideline as well) can help solve the puzzle of asthma diagnosis and management.