Abnormal exertional breathlessness on cardiopulmonary cycle exercise testing in relation to self-reported and physiological responses in chronic airflow limitation
Bibliographic record
Abstract
Background: Exertional breathlessness is a cardinal symptom of cardiorespiratory disease. Research Question: How does breathlessness abnormality graded using normative reference equations during cardiopulmonary exercise testing (CPET) relate to self-reported and physiological responses in people with chronic airflow limitation (CAL). Study Design and Methods: Analysis of people aged ≥40 years with CAL undergoing CPET in the Canadian Cohort Obstructive Lung Disease study. Breathlessness intensity ratings (Borg 0-10 category ratio scale [CR10]) were evaluated in relation to power output (W), rate of oxygen uptake (V'O2), and minute ventilation (V'E) at peak exercise using normative reference equations as: 1) probability of breathlessness normality (probability of having an equal or greater Borg CR10 rating among healthy; lower probability reflecting more severe breathlessness); and 2) presence of abnormal breathlessness (rating above the upper limit of normal [ULN]). Associations with relevant participant-reported and physiologic outcomes were evaluated. Results: We included 330 participants (44% women): mean±SD age 64±10 years (range 40-89), FEV1/FVC 57.3±8.2%, FEV1 75.6±17.9%predicted. Abnormally low exercise capacity (peak V'O2< lower limit of normal) was present in 26%. Relative to peak W, V'O2 and V'E, abnormally high breathlessness was present in 26%, 25% and 18% of participants. For all equations, abnormally high exertional breathlessness was associated with worse lung function, exercise capacity, self-reported symptom burden, physical activity, health-related quality of life; and greater physiological abnormalities during CPET. Interpretation: Abnormal breathlessness graded using CPET normative reference equations was associated with worse clinical, physiological, and functional outcomes in people with CAL supporting construct validity of abnormal exertional breathlessness.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 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".