Guidelines for the diagnosis and management of asthma: a look at the key differences between BTS/SIGN and NICE

NICE reports that, in its pilot study in seven practices, its algorithm could be completed in 55% of patients with suspected asthma; a diagnosis of asthma was confirmed in 25% of cases; with 20% reaching no diagnosis despite completing the algorithm. 9 BTS/SIGN used the same diagnostic test evidence, but also explicitly searched for pragmatic studies reporting evaluation of diagnostic programmes and, in discussion with the clinical guideline development group members, derived a 'good practice' algorithm. BTS/SIGN suggest that existing evidence of atopic status (blood eosinophils, skin prick testing, IgE) may influence the probablity of asthma, but agree with NICE that they should not be considered as 'diagnostic tests'; their key value may prove to be in establishing phenotypes of asthma or identifying triggers that may inform management. 11 Spirometry is positioned as pivotal by both guidelines, but both caution that it is not useful for ruling out asthma because the sensitivity is low, especially in primary care populations (only 27% of people diagnosed as having asthma in the NICE feasibility work had obstructive spirometry which is similar to the estimate in BTS/SIGN of 'a quarter having obstructive spirometry'). [...]the pattern of asthma in preschool children is heterogeneous and different from adults. Neither guideline addresses the issue of what to do with the child who is having frequent wheezing attacks treated with short courses of oral corticosteroids, but who has no interval asthma symptoms. 9 First-line preventer treatment in children under 5 with probable asthma and poor symptom control In young children with symptoms uncontrolled by intermittent reliever use in whom maintenance therapy is being considered, regular daily inhaled corticosteroid is the first-line preventer of choice although both BTS/SIGN and NICE acknowledge that the evidence base is limited.