The ‘clinically significant’ bronchodilator responsiveness (BDR) in children: a comparative study between six definitions of scholarly societies and a mini-review

ABSTRACT

Objective: To compare the percentages of children with and without airway obstruction (obstructive and non-obstructive groups, respectively) presenting a ‘clinically significant’ BDR according to the following definitions: GINA: FEV₁ increase >12% predicted (∆_Predicted), ATS/ERS: FEV₁ increase ≥12% initial (∆_Initial) and ∆FEV₁ absolute (∆) ≥200 ml and/or ∆FVC_Initial ≥12% and ∆FVC ≥200 ml, British thoracic society (BTS): ∆FEV_1Initial ≥12%, National asthma education and prevention program (NAEPP): ∆FEV_1Initial ≥12% and ∆FEV₁ > 200 ml, Group of research on advances in pediatric pneumology: ∆FEV_1Initial ≥12% or ∆PEF_Initial ≥20%, and South African thoracic society (SATS): ∆FEV_1Initial ≥12% or ∆FEV₁ >200 ml and/or ∆FVC_Initial ≥12% or ∆FVC >200 ml.

Methods: This was a multicenter comparative study involving 278 children aged 6 to16 years: obstructive group (FEV₁/FVC < lower-limit-of-normal, n = 116) and non-obstructive group (FEV₁/FVC ≥ lower-limit-of-normal, n = 162). Spirometry was performed before/after a bronchodilator test. The Cochrane Q test was used to compare the percentage of responders according to the six definitions.

Results: The percentages of responders among the obstructive [ranging from 51.72 (NAEPP) to 74.14% (SATS)] and the non-obstructive [ranging from 0.62 (NAEPP, BTS) to 8.64% (SATS)] groups were definition-dependent.

Conclusion: In children, a ‘clinically significant’ BDR is definition-dependent.

KEYWORDS:

• Bronchodilator agents
• reversibility
• guideline

Article highlights

• Scholarly societies [eg, GINA, ATS/ERS, South African thoracic society (SATS), Research group on advances in pediatric pneumology, National asthma education and prevention program (NAEPP), British thoracic society (BTS)] ‘failed’ to adopt a clear consensus about what constitutes a ‘clinically significant’ bronchodilator responsiveness (BDR) in children.

• Three issues were raised: which spirometric data to use [FEV₁ and/or FVC and/or peak expiratory flow]? Which expression to retain [absolute change (Δ) and/or change expressed as a percentage of the predicted value (Δ_Predicted) and/or change expressed as a percentage of the initial value (Δ_Initial)]? Which significant thresholds to apply?

• BDR in children with (n=116) and without (n=162) an airway obstruction was dependent on the scholarly societies’ definition.The percentages of responders having a ‘clinically significant’ bronchodilator responsiveness varied from 51.72 (NAEPP: ΔFEV_1Initial ≥ 12% and ΔFEV₁ > 0.2 l) to 74.14% (SATS: ΔFEV_1Initial ≥ 12% or ΔFEV₁ > 0.2 l and/or ΔFVC_Initial ≥ 12% or ΔFVC > 0.2 l) among the obstructive group, and from 0.62 (NAEPP, BTS: ΔFEV_1Initial ≥ 12%) to 8.64 (SATS) among the non-obstructive group.

Supplemental data

Supplemental data for this article can be accessed here.

Acknowledgments

The authors wish to thank Professor Samir Boukattaya for his invaluable contribution in the improvement of the quality of the writing in the present article.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Declaration of interest

H Ben Saad has received personal fees from AstraZeneca, Saiph, Teriak, Opalia Recordati and Chiesi. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Data availability statement

Data will be available upon request from the corresponding author ([email protected])

Previous presentations

The abstract of this paper was presented during the European Respiratory Society International Congress, ERS 2019 (Madrid (Spain): 28 September - 2 October 2020) and published in the European Respiratory Journal: Guezguez F, Knaz H, Anane I, Bougrida M, Ben Saad H. How to interpret bronchodilator response (BDR) in children? Eur Respir J 2019 54: PA1131; DOI: 10.1183/13993003.congress-2019.PA1131.

Additional information

Funding

This study was not funded.