The 6-Minute Walk Test in Chronic Respiratory Failure: Does Observed or Predicted Walk Distance Better Reflect Patient Functional Status?
Bibliographic record
Abstract
BACKGROUND: Acquiring 6-min walk test (6MWT) data from patients undergoing noninvasive mechanical ventilation due to chronic hypercapnic respiratory failure is limited. We aimed to assess whether the actual 6-min walk distance (6MWD) or the percent predicted 6MWD is a better reflection of the respiratory function of patients using home noninvasive ventilation (NIV) due to chronic hypercapnic respiratory failure. METHODS: This was a cross-sectional observational study. The 6MWT was performed in subjects using home NIV. Diagnoses were grouped as COPD, obesity hypoventilation syndrome (OHS), kyphoscoliosis, and parenchymal lung disease. Sex, age, and body mass index (BMI) were used to calculate ideal 6MWD. Male: 1,140 m - (5.61 × BMI) - (6.94 × age), and subtract 153 m for the lower limit of normal. Female: 1,017 m - (6.24 × BMI) - (5.83 × age), and subtract 139 m for the lower limit of normal. The 6MWD and percent-of-predicted 6MWD were compared relative to arterial blood gas, spirometry values, and diagnosis. RESULTS: The 6MWT was performed in 144 subjects, median (IQR) age 62 y (55-71 y). The male/female ratio, median (IQR) 6MWD, and percent-of-predicted 6MWD values were: COPD 32/6, 316 m (226-390 m), and 59.4% (42.5-68.9%); OHS 24/28, 303 m (240-362 m), and 73.0% (63.0-82.0%); kyphoscoliosis 16/7, 420 m (318-462 m), and 70.5% (56.0-75.2%); and parenchymal lung disease 19/12, 333 m (273-372 m), and 67.1% (46.7-74.7%). The correlation of percent-of-predicted 6MWD with spirometry and arterial blood gas values were better than with the actual 6MWD. CONCLUSIONS: The percent-of-predicted 6MWD was better correlated with respiratory function than actual 6MWD for subjects using home NIV due to chronic hypercapnic respiratory failure with COPD, OHS, kyphoscoliosis, and parenchymal lung disease.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".