Small-airway obstruction, dynamic hyperinflation, and gas trapping despite normal airway sensitivity to methacholine in adults with chronic cough
Bibliographic record
Abstract
The clinical relevance of cough during methacholine challenge in individuals with normal airway sensitivity is unknown. We compared responses of individuals with chronic cough who cough during high-dose methacholine bronchoprovocation and have normal versus increased airway sensitivity to healthy controls. Fifteen healthy participants (CONTROL) aged 26 ± 7 yr (mean ± SD) and 32 participants aged 42 ± 14 yr with chronic cough and suspected asthma completed high-dose methacholine challenge testing. Three participants who did not cough and had normal airway sensitivity were excluded. Spirometry and lung volumes were compared at the maximum response (MAX) among 1) ASTHMA [ n = 15, provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (FEV1) from baseline (PC20) 4.71 ± 1.37 mg/ml], 2) methacholine-induced cough with normal airway sensitivity (COUGH, n = 14, PC20 41.2 ± 18.7 mg/ml for 3 participants with a measurable PC20), and 3) CONTROL ( n = 15; PC20 93.4 ± 95.4 mg/ml for 4 participants with a measurable PC20). Esophageal pressure-derived pulmonary mechanics were compared at MAX for the ASTHMA and COUGH groups. From baseline to MAX, FEV1 and forced expiratory flow between 25% and 75% of forced vital capacity decreased more in ASTHMA (−36.2 ± 3.8 %pr; −47.1 ± 6.9 %pr, respectively) than COUGH (−12.2 ± 3.0 %pr ( P < 0.001); −24.7 ± 6.5 %pr ( P < 0.001), respectively) and CONTROL (−13.7 ± 2.0 %pr ( P < 0.001); −32.8 ± 5.4 %pr ( P < 0.017), respectively). In both ASTHMA and COUGH, inspiratory capacity decreased by 500–800 ml, and functional residual capacity and residual volume increased by ~800 ml. Individuals with COUGH develop dynamic hyperinflation and gas trapping comparable to individuals with ASTHMA despite less bronchoconstriction and smaller reductions in mid-to-late expiratory flows, which leads us to believe that COUGH is a distinct phenotype. NEW & NOTEWORTHY Healthy individuals and individuals with chronic cough who demonstrate normal airway sensitivity but cough during methacholine bronchoprovocation bronchoconstrict less than individuals with mild asthma. However, those who cough and have normal airway sensitivity develop dynamic hyperinflation and gas trapping comparable to individuals with mild asthma. Thus, methacholine-induced cough with normal airway sensitivity may be clinically relevant, related to reversible small airway obstruction and preservation of the bronchodilating and/or bronchoprotective effects of deep inspirations.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".