Diagnostic Accuracy of NICE Asthma Algorithm Poor in Children

The diagnostic algorithm for pediatric asthma proposed by the United Kingdom National Institute for Health and Care Excellence (NICE) is an inappropriate tool for use in children and adolescents, according to a population-based cohort study reported in The Lancet.¹

In their analysis, investigators from various hospitals in Manchester, United Kingdom, challenged multiple features of the NICE algorithm when applied specifically to adolescents and concluded that it should not be used in children. The researchers looked at follow-up data available during the period between July 2011 and November 2014 in 772 children born into the Manchester Asthma and Allergy Study cohort to prospectively test the algorithm. At the time of follow-up, the children were all between the age of 13 and 16. 

Spirometry was the first-line measure of lung function recommended in the NICE algorithm. In the cohort, 10 of 630 children who completed spirometry met the NICE criteria for asthma (according to a ratio of forced expiratory volume [FEV1] to forced vital capacity [FVC] assessment, with a cutoff of 70%), and of those children, only 2 were currently diagnosed with asthma.

The algorithm sequence then called for a bronchodilator reversibility test, followed by a fractional exhaled nitric oxide (FeNO) measurement as a marker of allergic airway inflammation, and, lastly, a recording of peak expiratory flow variability during 2 to 4 weeks, if necessary.²

Of these measurements, FeNO measurement was by far the most sensitive test evaluated, with positive results (≥35 parts per billion [ppb]) in nearly a quarter of the total pediatric cohort, and in 44% of symptomatic children (15 of 34 participants). Conversely, most of the 54 children who tested positive for bronchodilator reversibility did not have obstructive spirometry, and assessment of peak flow variability was deemed largely not useful owing to dependence on manual diaries, which can be unreliable in children.

In the symptomatic children who completed 3 of the 4 tests included in the NICE algorithm, the researchers were able to definitively diagnose asthma in only 2 children. However, neither child met the researchers’ “epidemiologic definition,” suggesting an obvious need for studies that specifically investigate diagnostic tests for asthma appropriate for the pediatric population.

The investigators also negated the validity of “the values defined for spirometry, the order in which the tests are done, and the position of bronchodilator reversibility within the algorithm sequence, which seems to add little when tested in this population.”¹

Their data suggested benefits to measuring FeNO first in children, as 90% of the cohort required this, and that a cutoff of 37 ppb was a better indicator in this age group.

The main limitation to this study was the narrow age range of the population because the results cannot be extrapolated to apply to children younger than 13 years.

References

2. National Institute for Health and Care Excellence (NICE). Asthma: diagnosis and monitoring of asthma in adults, children and young people. Clinical guideline, methods, evidence and recommendations.

www.nice.org.uk/guidance/gid-cgwave0640/resources/asthma-diagnosis-and-monitoring-draft-guideline2. Published January 2015. Accessed August 22, 2017.