Bibliographic record
Abstract
Long-term natural history of chronic obstructive pulmonary disease: severe exacerbations and mortality Samy Suissa,1,2 Sophie Dell’Aniello,1 Pierre Ernst1,3 Background The long-term natural history of chronic obstructive pulmonary disease (COPD) in terms of successive severe exacerbations and mortality is unknown. Methods The authors formed an inception cohort of patients from their first ever hospitalisation for COPD during 1990e2005, using the healthcare databases from the province of Quebec, Canada. Patients were followed until death or 31 March 2007, and all COPD hospitalisations occurring during follow-up were identified. The hazard functions of successive hospitalised COPD exacerbations and all-cause mortality over time were estimated, and HRs adjusted for age, sex, calendar time and comorbidity. Results The cohort included 73 106 patients hospitalised for the first time for COPD, of whom 50 580 died during the 17-year follow-up, with 50 % and 75 % mortality at 3.6 and 7.7 years respectively. The median time from the first to the second hospitalised exacerbation was around 5 years and decreased to <4 months from the 9th to the 10th. The risk of the subsequent severe exacerbation was increased threefold after the second severe exacerbation and 24-fold after the 10th, relative to the first. Mortality after a severe exacerbation peaked to 40 deaths per 10 000 per day in the first week after admission, dropping gradually to 5 after 3 months. Conclusions The course of COPD involves a rapid decline in health status after the second severe exacerbation and high mortality in the weeks following every severe exacerbation. Two strategic targets for COPD management should include delaying the second severe exacerbation and improving treatment of severe exacerbations to reduce their excessive early 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 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.006 | 0.003 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.486 | 0.282 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".