Abnormally high exertional breathlessness predicts mortality in people referred for incremental cycle exercise testing
Bibliographic record
Abstract
BACKGROUND: Exertional breathlessness is a key symptom in cardiorespiratory disease and can be quantified using incremental exercise testing, but its prognostic significance is unknown. We evaluated the ability of abnormally high breathlessness intensity during incremental cycle exercise testing to predict all-cause, respiratory, and cardiac mortality. STUDY DESIGN AND METHODS: Longitudinal cohort study of adults referred for exercise testing followed prospectively for mortality assessed using the Swedish National Causes of Death Registry. Abnormally high exertional breathlessness was defined as a breathlessness intensity response (Borg 0-10 scale) > the upper limit of normal using published reference equations. Mortality was analyzed using multivariable Cox regression, unadjusted and adjusted for age, sex, and body mass index. A further mortality analysis was also done adjusted for select common comorbidities in addition to age, sex and body mass index. RESULTS: Of the 13,506 people included (46% female, age 59±15 years), 2,867 (21%) had abnormally high breathlessness during exercise testing. Over a median follow up of 8.0 years, 1,687 (12%) people died. No participant was lost to follow-up. Compared to those within normal predicted ranges, people with abnormally high exertional breathlessness had higher mortality from all causes (adjusted hazard ratio [aHR] 2.3, [95% confidence interval] 2.1-2.6), respiratory causes (aHR 5.2 [3.4-8.0]) and cardiac causes (aHR 3.0 [2.5-3.6]). Even among people with normal exercise capacity (defined as peak Watt ≥75% of predicted exercise capacity, n = 10,284) those with abnormally high exertional breathlessness were at greater risk of all-cause mortality than people with exertional breathlessness within the normal predicted range (aHR 1.5 [1.2-1.8]). CONCLUSION: Among people referred for exercise testing, abnormally high exertional breathlessness, quantified using healthy reference values, independently predicted all-cause, respiratory and cardiac mortality.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".