Minimal Important Difference for Physical Activity and Validity of the International Physical Activity Questionnaire in Interstitial Lung Disease
Bibliographic record
Abstract
RATIONALE: The optimal method of physical activity measurement has not been determined in patients with fibrotic interstitial lung disease (ILD). OBJECTIVES: To assess the validity, internal consistency, and responsiveness of the International Physical Activity Questionnaire long form (IPAQ-LF) and to estimate the minimal important difference (MID) for moderate to vigorous physical activity (MVPA) in patients with fibrotic ILD. METHODS: This two-center prospective cohort study included a convenience sample of 111 outpatients with fibrotic ILD who wore waist and wrist ActiGraph accelerometers for 7 consecutive days, followed by self-administration of the IPAQ-LF. Both measurements were performed at baseline and 6-month follow-up. Spearman rank correlations were used to evaluate the IPAQ-LF validity in comparison to activity monitor data, lung function, step count, and quality of life. The internal consistency of the IPAQ-LF was determined using Cronbach's α. Self-reported changes in IPAQ-LF parameters were compared among tertiles of change measured by the waist activity monitor to assess the responsiveness of the IPAQ-LF after 6 months. Anchor- and distribution-based methods were used to estimate the MID for MVPA. RESULTS: Self-reported MVPA minutes, activity-related energy expenditure, sedentary time, and inactive time of the IPAQ-LF generally showed moderate to strong correlations with corresponding waist activity monitor data, step count, lung function, and quality of life. The Cronbach's α of the IPAQ-LF was 0.78. The IPAQ-LF was responsive at detecting increases in weekly MVPA and energy expenditure. The MIDs for MVPA were 8 to 26 and 13 to 58 min/wk using the anchor-based method for waist activity monitor and IPAQ-LF data, respectively. The distribution-based MID estimate for MVPA was 104 to 242 min/wk. CONCLUSIONS: The IPAQ-LF has acceptable validity and internal consistency for measuring daily physical activity in patients with fibrotic ILD. The IPAQ-LF was responsive at detecting increases in physical activity but limited in its ability to detect declines or changes in inactivity. Using an anchor-based approach, the MID for MVPA measured by a waist activity monitor is approximately 26 min/wk.
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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 | 0.017 | 0.050 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".