Asthma pathway (BTS, NICE, SIGN) [SIGN 244]
Why the committee made the recommendation
The committee agreed that there is some information that should always be obtained at a routine monitoring review, for example whether any courses of oral corticosteroid have been needed since the last review.
Symptom questionnaires and diaries
The committee looked at evidence on the effects of monitoring asthma control using symptom questionnaires given at intervals ranging from weekly to twice in 3 months. Although there were a small number of beneficial outcomes in individual studies, overall, there was no clinically useful effect of the monitoring in either adults or children. The committee noted that the interventions were complex, as they assessed the effects not just of the symptom monitoring but also the therapeutic adjustments made in response to the questionnaire result. Nonetheless, they concluded that they should not recommend questionnaires used at these relatively frequent intervals.
The committee were aware of evidence (that was not part of this review) showing that the results of asthma control questionnaires predict the risk of future asthma attacks. They therefore used their experience to recommend that questionnaires should be used as part of any asthma-related review. For most people this will be their annual review.
Pulmonary function
The committee looked for evidence on the use of spirometry and PEF monitoring as measures of asthma control but did not find any data on spirometry used in this context.
There was evidence on PEF monitoring in both adults and children. The monitoring was typically linked to treatment changes triggered by designated thresholds of PEF and compared with the effects of treatment changes triggered by symptoms. In adults, regular PEF measurement was associated with worse quality-of-life parameters. The committee thought that this might be explained by regular monitoring inducing anxiety in some people if PEF is not consistently high, and by the inconvenience of making regular measurements.
In both adults and children, PEF monitoring was associated with an increase in asthma attacks, which appears to be a further disadvantage of regular monitoring. The committee found this hard to explain as monitoring itself seems unlikely to make asthma worse. It is possible that PEF measurements may have led to quicker identification and appropriate early treatment of some attacks. However, if this is the case, one might expect to see a reduction in the need for hospitalisation, or time off work or school, and these potential benefits were not seen.
The committee agreed that a minority of people with asthma benefit from regular measurement of PEF, for example those who are poor at perceiving changes in their airways and are therefore at risk of delaying treatment of asthma attacks. They also took into account evidence in adults that was not part of the formal review showing that action plans that incorporate PEF measurement can be beneficial. So, they recommended against the use of routine PEF monitoring, with the caveat that it might have value in some circumstances.
FeNO
The evidence showed that, in both adults and children, regular FeNO monitoring led to a reduction in the number of asthma exacerbations. In children there was also a significant improvement in lung function. In adults, the reduction in exacerbations was achieved alongside an overall reduction in the dosage of maintenance ICS therapy. This was not the case in children, but the studies in this age group were more likely to be conducted in secondary or tertiary care, so it is likely that they had a higher maintenance therapy requirement.
The committee concluded that FeNO monitoring was cost-effective in adults but may not be in children. It was not possible on the current evidence to say what the optimum frequency of monitoring should be, but the committee agreed that an appropriate opportunity would be to make a routine measurement at the person’s regular review (which will be an annual review for most people).
The FeNO level is a proxy measure of airway inflammation. It can therefore be very useful in determining how to adjust treatment, or as an indicator of treatment adherence, when a person with asthma has poor symptom control. Conversely, when symptom control is excellent and the possibility of reducing maintenance therapy arises, a normal FeNO level provides helpful reassurance. The committee therefore agreed that a FeNO measurement should be considered whenever a change in maintenance therapy might be appropriate.
How the recommendation might affect practice
Asthma control questionnaires are already recommended as part of an annual review. Therefore, no change to practice is anticipated. The recommendations on pulmonary function are expected to reduce the use of PEF monitoring.
Measurement of FeNO is increasingly used in secondary care asthma clinics, but in primary care only a minority of GP practices have on-site access to the test. Regular FeNO monitoring represents a significant change in practice because most people with asthma are managed in primary care. This change will also carry a cost. The committee noted that FeNO measurement is also useful in diagnosing asthma (see the section on objective tests for diagnosing asthma), and increased access to the test will therefore be of dual benefit.
Full details of the evidence and the committee’s discussion are in: