Affiliation:
1. Department of Paediatric Respiratory and Sleep Medicine Queensland Children's Hospital Brisbane Queensland Australia
2. Children's Health and Environment Program, Child Health Research Centre The University of Queensland Brisbane Queensland Australia
3. Centre for Health Services Research, Faculty of Medicine The University of Queensland Brisbane Queensland Australia
Abstract
AbstractBackgroundSeveral techniques can be used to assess bronchodilator response (BDR) in preschool‐aged children, including spirometry, respiratory oscillometry, the interrupter technique, and specific airway resistance. However, there has not been a systematic comparison of BDR thresholds across studies yet.MethodsA systematic review was performed on all studies up to May 2023 measuring a bronchodilator effect in children 2–6 years old using one of these techniques (PROSPERO CRD42021264659). Studies were identified using MEDLINE, Cochrane, EMBASE, CINAHL via EBSCO, Web of Science databases, and reference lists of relevant manuscripts.ResultsOf 1224 screened studies, 43 were included. Over 85% were from predominantly European ancestry populations, and only 22 studies (51.2%) calculated a BDR cutoff based on a healthy control group. Five studies included triplicate testing with a placebo to account for the within‐subject intrasession repeatability. A relative BDR was most consistently reported by the included studies (95%) but varied widely across all techniques. Various statistical methods were used to define a BDR, with six studies using receiver operating characteristic analyses to measure the discriminative power to distinguish healthy from wheezy and asthmatic children.ConclusionA BDR in 2‐ to 6‐year‐olds cannot be universally defined based on the reviewed literature due to inconsistent methodology and cutoff calculations. Further studies incorporating robust methods using either distribution‐based or clinical anchor‐based approaches to define BDR are required.