Effectiveness of Inhaled Corticosteroids in Chronic Obstructive Pulmonary Disease
Bibliographic record
Abstract
Recent large-scale cohort studies that reported an important reduction in mortality and chronic obstructive pulmonary disease (COPD) morbidity with inhaled corticosteroids may be biased. We used a population-based cohort of Saskatchewan residents 55 years of age or over, first hospitalized for COPD during 1990 to 1997, to study this potential bias. These 979 subjects were followed for a year from discharge until their first readmission for COPD or death (389 subjects). Inhaled corticosteroid exposure was measured as any dispensing within 90 days after discharge. Cox's proportional hazards model was used to compare the time-fixed analysis employed in the recent studies with the alternative time-dependent analysis. The time-fixed adjusted rate ratio was 0.69 (95% CI: 0.55-0.86) for inhaled corticosteroid use within 90 days, whereas the time-dependent rate ratio was 1.00 (95% CI: 0.79-1.26). With the time-fixed analysis, the rate ratios were affected by the length of the exposure period, decreasing from 0.98 for a 15-day exposure period to 0.51 for 365 days, but remained stable between 1.06 and 0.94 with the time-dependent analysis. Inhaled corticosteroid use after hospitalization for COPD was not found to reduce mortality and morbidity. Although observational studies can be valuable, the recent reports of reductions in mortality and morbidity with inhaled corticosteroids are biased by their inappropriate allocation of exposure and analysis of immortal time.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.003 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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 teacher head, 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".