Assessment of bronchodilator response using forced oscillation technique in paediatric asthmatic patients from Central India: A cross-sectional study
Year: 2026
Type: article
Abstract: Dear Editor, We read with great interest the cross-sectional study by Rathod et al. on Assessment of bronchodilator response using forced oscillation technique in paediatric asthmatic patients from Central India: A cross-sectional study. The authors should be commended for addressing an important gap in regional Oscillometric data. We, however, wish to highlight certain methodological and interpretative concerns that may influence the clinical applicability of their findings.[1] First, the study reports impressively high percentage changes in R5–20 (e.g., median 93.7% in older males), which appear notably larger than those commonly seen in paediatric oscillometry literature. The European Respiratory Society (ERS) technical standards note that bronchodilator responsiveness in children is often modest and merits cautious interpretation due to variability in resistance measures and frequency dependence. Similarly, prior studies indicate smaller bronchodilator response (BDR) shifts in R5 and X5 relative to spirometry, possibly due to baseline dependency in percentage calculations. We kindly suggest that including absolute pre- and post-bronchodilator values, along with the coefficient of variation, could provide valuable context and help clarify whether these notable changes arise from low baseline impedance or robust bronchodilation.[2,3] Second, while the authors conclude that reactance area (Ax) and R5–20 serve as sensitive markers of airway reversibility, we note that Ax data were unavailable for a considerable portion of participants, especially younger females. With missing data nearing 40%–45%, there may be a risk of bias and reduced statistical reliability. The ERS oscillometry guidelines highlight the need for reproducibility criteria and complete acceptable trials to support reliable interpretation of reactance indices like area of reactance (Ax). In small paediatric cohorts, such incomplete measurements might stem from technical difficulties or upper airway artefacts, which could benefit from further discussion before affirming marker sensitivity. We respectfully suggest exercising added caution in these interpretations.[4] Third, although the study notes interesting age- and gender-based trends in BDR, we observe that none of the comparisons achieved statistical significance following Bonferroni correction. It may be helpful to interpret these non-significant findings cautiously to avoid potential overemphasis, especially in analyses with smaller subgroups. The American Statistical Association advises that the lack of statistical significance should not be presented as evidence of differences without sufficient power or predefined hypotheses. Additionally, studies in paediatric oscillometry often find that sex-related differences in airway mechanics tend to be modest and frequently influenced by anthropometric factors rather than inherent biological distinctions. We kindly suggest considering these aspects when discussing the clinical implications of the observed trends.[5] Finally, while FOT offers clear benefits for young children unable to perform reliable spirometry, we note that the study did not incorporate healthy controls, spirometric correlations, or diagnostic accuracy assessments. International asthma guidelines recommend interpreting bronchodilator response in relation to established normative data or validated cutoffs. Without external validation or receiver-operating characteristic analyses, the internal “data-driven” thresholds may have limited generalizability beyond this specific cohort. We appreciate the authors’ efforts and suggest these additions could further enhance the findings’ applicability.[6] In conclusion, this study provides useful regional data on paediatric oscillometry; nevertheless, clarity on the size of the percentage change, treatment of missing Ax data, and cautious interpretation of non-significant subgroup trends would improve its translational value. We applaud the authors’ efforts and hope that these findings inspire more large-scale, controlled investigations to improve Oscillometric BDR criteria in Indian youngsters. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Source: Lung India
Authors: Sandhya Saini, Kanika Kanika
Institution: Maharishi Markandeshwar University, Mullana
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7165776010