Obesity and Chronic Obstructive Pulmonary Disease: Is Fatter Really Better?
Bibliographic record
Abstract
BACKGROUND: Overweight⁄obesity is associated with longer survival in chronically ill patients, a phenomenon referred to as the 'obesity paradox'. OBJECTIVE: To investigate whether the obesity paradox in patients with chronic obstructive pulmonary disease (COPD) is due to fat accumulation or confounding factors. METHODS: A total of 190 patients with stable COPD who underwent a mean (± SD) follow-up period of 72±34 months were enrolled. Anthropometry, pulmonary function tests, midthigh muscle cross-sectional area obtained using computed tomography (MTCSACT), arterial blood gas and exercise testing data were measured at baseline. Patients were categorized into two subgroups according to body mass index (BMI) <25 kg⁄m2 or ≥25 kg⁄m2 (normal and overweight⁄obese, respectively). RESULTS: Seventy-two patients (38%) died during the follow-up period. Survival tended to be better in the overweight⁄obese patients but this difference did not reach statistical significance. Overweight⁄obese patients had better lung function and a larger MTCSACT than those with normal BMI (P<0.001). Overweight⁄obese patients also had a significantly higher peak work rate than patients with normal BMI (P<0.001). PaO2 and PaCO2 were not significantly different in the two groups. When adjusted for PaCO2, peak work rate and MTCSACT, the tendency for improved survival in overweight⁄obese patients disappeared. In fact, when these variables were considered in the survival analysis, patients with lower BMI tended to have better survival. CONCLUSION: These results suggest that important confounders, such as hypercapnia, exercise capacity and muscle mass, should be considered when interpreting the association between increased BMI and survival in patients with COPD.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".