Comparison of two standardized methods of methacholine inhalation challenge in young adults
Bibliographic record
Abstract
In the European Community Respiratory Health Study (ECRHS), airway responsiveness to methacholine was determined using the Mefar dosimeter protocol. Elsewhere, the 2-min tidal breathing method has become the preferred standardized method. The relationship between measurements of responsiveness by these two methods is not well established. This study measured airway responsiveness to methacholine by dosimeter and tidal breathing methods in 47 healthy asthmatic subjects aged 20-44 yrs. Tests were performed within 1 week and in random order. Baseline forced expiratory volume in one second (FEV1) varied by <10% between tests in 42/47 subjects. There was a close association between responsiveness determined by the two methods. A provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) value of < or =8.0 mg x mL(-1) (tidal method) used to categorize airway hyperresponsiveness agreed most closely with a provocative dose of methacholine causing a 20% fall in FEV1 (PD20) value of < or =0.5 mg (dosimeter method) (kappa statistic 0.78). Each doubling or halving of PC20 to define a level of hyperresponsiveness agreed closely with a doubling or halving of PD20. Assessment of airway responsiveness as provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second by the Mefar dosimeter protocol gave a close and predictable relationship with provocative concentration of methacholine causing a 20% fall in expiratory volume in one second assessed using the tidal breathing method. Airway hyperresponsiveness as determined by the accepted criterion of provocative concentration of methacholine causing a 20% fall in expiratory volume in one second < or =8 mg x mL(-1) was best correlated with provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second <0.5 mg by Mefar dosimeter.
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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 | 0.009 | 0.022 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".