Authors: Valadkhani, Arman et al.
Anesthesiology October 2025 | DOI: 10.1097/ALN.0000000000005779
This large prospective cohort study evaluated the relationship between preoperative functional capacity—measured in metabolic equivalents of task (METs)—and postoperative outcomes across a broad elective surgical population. While functional capacity is a cornerstone of preoperative risk assessment, this study explored its predictive value using granular MET categories rather than simple binary cutoffs.
The investigators analyzed data from 38,293 adults undergoing elective noncardiac surgery at two Karolinska University Hospital sites between 2020 and 2023. Patients were categorized by self-reported functional capacity into five MET levels: 1, 2–3, 4–5, 6–8, and ≥9. The primary outcomes were all-cause mortality at 30 and 365 days; secondary outcomes were days alive and at home (DAH30, DAH365).
Mortality increased markedly with lower MET levels. Thirty-day and one-year mortality rates were 0.6% and 5.4%, respectively. In adjusted models, relative median survival decreased progressively as functional capacity declined compared to the MET ≥ 9 group: 0.75 for MET 6–8, 0.52 for MET 4–5, 0.39 for MET 2–3, and 0.24 for MET 1. The adjusted marginal risk difference in one-year mortality rose sharply across categories—from 0.8% for MET 6–8 to 7.2% for MET 1. Similarly, lower MET levels correlated with fewer days alive and at home during the year after surgery.
The authors conclude that self-reported MET levels exhibit a clear, dose-dependent relationship with both short- and long-term postoperative mortality and morbidity. Incorporating detailed MET categorization into preoperative assessments enhances risk discrimination and supports its continued use as a simple yet powerful functional measure for surgical risk stratification.
What You Should Know
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Lower preoperative MET levels strongly predict higher postoperative mortality and reduced functional recovery.
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Each one-step decline in MET category meaningfully increases 30- and 365-day mortality risk.
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Detailed MET classification improves precision in surgical risk assessment compared with binary thresholds.
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