Variability in forced expiratory volume in 1 s in children with symptomatically well-controlled asthma
Bibliographic record
Abstract
Aims Spirometry is used by many clinicians to monitor asthma in children but relatively little is understood about its variability over time. The aim of this study was to determine the variability of forced expiratory volume in 1 s (FEV 1 ) in children with symptomatically well-controlled asthma by applying three different methods of expressing change in FEV 1 over 3-month intervals. Methods Data from five longitudinal studies of children with asthma which measured FEV 1 at 3-month intervals over 6 or 12 months were used. We analysed paired FEV 1 measurements when asthma symptoms were controlled. The variability of FEV 1 % predicted (FEV 1 %), FEV 1 z-score (FEV 1 z) and conditional z score for change (Zc) in FEV 1 was expressed as limits of agreement. Results A total of 881 children had 3338 FEV 1 measurements on occasions when asthma was controlled; 5184 pairs of FEV 1 measurements made at 3-month intervals were available. Each unit change in FEV 1 z score was equivalent to a Zc 1.45 and an absolute change in FEV 1 % of 11.6%. The limits of agreement for change in FEV 1 % were −20 and +21, absolute change in FEV 1 z were −1.7 and +1.7 and Zc were −2.6 and +2.1. Regression to the mean and increased variability in younger children were present for change in FEV 1 % and FEV 1 z comparisons, but not Zc. Conclusion Given the wide limits of agreement of paired FEV 1 measurements in symptomatically well-controlled children, asthma treatment should primarily be guided by symptoms and not by a change in spirometry.
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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 | 0.003 | 0.013 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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 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".