Reliability of the American Society of Anesthesiologists physical status scale in clinical practice
Bibliographic record
Abstract
BACKGROUND: Previous studies, which relied on hypothetical cases and chart reviews, have questioned the inter-rater reliability of the ASA physical status (ASA-PS) scale. We therefore conducted a retrospective cohort study to evaluate its inter-rater reliability and validity in clinical practice. METHODS: The cohort included all adult patients (≥18 yr) who underwent elective non-cardiac surgery at a quaternary-care teaching institution in Toronto, Ontario, Canada, from March 2010 to December 2011. We assessed inter-rater reliability by comparing ASA-PS scores assigned at the preoperative assessment clinic vs the operating theatre. We also assessed the validity of the ASA-PS scale by measuring its association with patients' preoperative characteristics and postoperative outcomes. RESULTS: The cohort included 10 864 patients, of whom 5.5% were classified as ASA I, 42.0% as ASA II, 46.7% as ASA III, and 5.8% as ASA IV. The ASA-PS score had moderate inter-rater reliability (κ 0.61), with 67.0% of patients (n=7279) being assigned to the same ASA-PS class in the clinic and operating theatre, and 98.6% (n=10 712) of paired assessments being within one class of each other. The ASA-PS scale was correlated with patients' age (Spearman's ρ, 0.23), Charlson comorbidity index (ρ=0.24), revised cardiac risk index (ρ=0.40), and hospital length of stay (ρ=0.16). It had moderate ability to predict in-hospital mortality (receiver-operating characteristic curve area 0.69) and cardiac complications (receiver-operating characteristic curve area 0.70). CONCLUSIONS: Consistent with its inherent subjectivity, the ASA-PS scale has moderate inter-rater reliability in clinical practice. It also demonstrates validity as a marker of patients' preoperative health status.
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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 | 0.031 | 0.098 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| 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".