Misdiagnosis of children’s asthma is common in UK primary care and can be improved with objective tests

Abstract

Introduction: Both under and over diagnosis of children’s asthma have been reported. Objective tests may facilitate diagnosis but are not routinely available in UK primary care. Objective: To investigate the impact of spirometry and exhaled nitric oxide (eNO) tests on asthma diagnosis. Methods: Practice nurses in 10 general practices in Leicestershire were trained to use spirometry and eNO to inform asthma reviews. Children (5-16yr) were invited for review if a) diagnosed with asthma or b) not diagnosed but prescribed asthma medications in the past year. Spirometry defined airflow obstruction (AO) as FEV1 or FEV1/FVC Criteria used for asthma diagnosis: Confirmed = AO and +BDR Probable = AO and eNO≥35ppb without +BDR Possible = AO or eNO≥35ppb without +BDR Unlikely = good current symptom control, no exacerbations in the last 6mths, normal tests, and EITHER no regular inhaled corticosteroids OR had requested ≤50% of prescriptions Results: We saw 612 children and obtained valid data in 582. 147 (25%) children with valid data had no asthma diagnosis: 13 (9%) had asthma confirmed; 7 (5%) had probable, and 38 (26%) had possible asthma. Overall, 58 (40%) had abnormal lung function suggestive of asthma. 358 children with valid data had an existing asthma diagnosis: 15% met our criteria for unlikely to have asthma. Conclusion: – In our cohort, asthma overdiagnosis and underdiagnosis were potentially as high as 15% and 40% respectively. Providing objective tests in primary care can improve diagnosis of asthma in children.