Alpha<sub>1</sub>‐Antitrypsin Deficiency: A Position Statement of the Canadian Thoracic Society
Bibliographic record
Abstract
OBJECTIVE: To prepare new guidelines for the Canadian Thoracic Society (CTS) regarding severe alpha1-antitrypsin (AAT) deficiency and AAT replacement therapy. MATERIALS AND METHODS: Previously published guidelines and the medical literature about AAT deficiency and AAT replacement were reviewed. The prepared statement was reviewed and approved by the CTS Standards and Executive Committees. RESULTS: Three studies evaluated AAT replacement. The National Heart, Lung and Blood Institute's AAT Registry was a nonrandomized comparison of patients receiving and not receiving AAT replacement, and evaluated the decline in forced expiratory volume in 1 s (FEV1) in 927 subjects. The rate of FEV1 decline was significantly less in those receiving AAT treatment (66 +/- SE 5 mL/year versus 93 +/- SE 11 mL/year; P=0.03) only in the subgroup with FEV1 35% to 49% predicted. In another study comparing 198 German patients receiving weekly AAT infusions and 97 untreated Danish patients, the mean annual decline in FEV1 was significantly less in treated patients only in the subgroup with FEV1 31% to 65% predicted (62 mL versus 83 mL, P=0.04). Neither of these studies was a randomized, controlled study and, thus, cannot be taken as proof of efficacy. A randomized, double-blind, placebo controlled trial of monthly replacement therapy over three years in 56 exsmokers with severe AAT deficiency and moderate emphysema showed a trend (P=0.07) favouring slower progression of emphysema by computed tomography scan in the group receiving AAT replacement. CONCLUSIONS: AAT replacement therapy has not been proven definitively to be clinically effective in reducing the progression of disease in AAT-deficient patients, but there is a possible benefit to selected patients. A placebo controlled, randomized clinical trial of AAT replacement therapy is required. The authors recommend reserving AAT replacement therapy for AAT-deficient patients with impaired FEV1 of 35% to 50% predicted who have quit smoking and are on optimal medical therapy but continue to show a rapid decline in FEV1, and participation of all AAT-deficient subjects in the Canadian AAT Registry.
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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 | 0.013 | 0.013 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.003 | 0.003 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.009 | 0.006 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
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".