Impact of ERS/ATS changes in bronchodilator reversibility calculations on paediatric asthma diagnosis

Background: Demonstration of bronchodilator reversibility (BDR) is central to most asthma guidelines to confirm asthma. Previous ERS/ATS spirometry interpretation guidelines (Pellegrino 2005), and most current asthma guidelines, recommend a relative increase in FEV1 of ≥12% from baseline as significant BDR. Recently, alternative calculations have been suggested; FEV1 increase relative to predicted value (Stanojevic 2021), or FEV1 z-score change (Quanjer 2017). However, there is no corresponding consensus from asthma guidelines.

Aim: To explore the impact of BDR calculation on paediatric asthma diagnosis.

Method: Spirometry and BDR were performed in 180 children (5-16 years) with symptoms of asthma without a diagnosis. BDR was calculated for each participant. They were categorised as positive or negative using methods and thresholds recommended by Pellegrino, Stanojevic, and Quanjer.

Results: Compared with Pellegrino, concordance was 169/180 (94%) with Stanojevic and 146/180 (81%) with Quanjer. Based on the same test, 10-16% of children diagnosed with asthma using Pellegrino would not have asthma confirmed using alternative methods. Furthermore, 5-20% of children who did not have asthma confirmed using Pellegrino, would have using alternative calculations.

Conclusion: The BDR calculation used has important clinical implications for asthma diagnosis in children. Consensus on which to use is needed.