Authors: Valadkhani A. et al.
Anesthesiology, October 3, 2025. DOI: 10.1097/ALN.0000000000005779
This large, prospective dual-center cohort study assessed how preoperative functional capacity—expressed as metabolic equivalents of task (MET)—relates to postoperative mortality and morbidity. Although functional capacity has long been recognized as a predictor of surgical risk, prior studies often used binary cutoffs rather than examining graded associations across multiple MET levels.
The study enrolled 38,293 adults undergoing elective noncardiac surgery at Karolinska University Hospital (Solna and Huddinge) between 2020 and 2023. Preoperative MET levels were self-reported and grouped into five categories: 1, 2–3, 4–5, 6–8, and ≥9. Primary outcomes were all-cause mortality at 30 and 365 days. Secondary outcomes included days alive and at home at 30 and 365 days (DAH30 and DAH365), a patient-centered measure reflecting both survival and recovery quality.
Overall mortality was 0.6% at 30 days and 5.4% at one year. The risk of death increased progressively with decreasing MET levels in a clear dose-response pattern. Compared to patients with MET ≥9, adjusted models showed significantly shorter survival times for lower functional capacity groups:
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MET 6–8: relative median survival 0.75 (95% CI, 0.56–0.98)
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MET 4–5: 0.52 (0.40–0.68)
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MET 2–3: 0.39 (0.29–0.51)
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MET 1: 0.24 (0.16–0.34)
Likewise, the absolute 365-day mortality risk difference compared to MET ≥9 increased stepwise—from 0.8% for MET 6–8 up to 7.2% for MET 1. Lower MET categories also correlated with fewer DAH365, particularly among the most frail patients.
These findings establish that self-reported MET levels, even without formal exercise testing, strongly predict both short- and long-term surgical outcomes. Using more granular MET categories rather than dichotomous thresholds enhances preoperative risk stratification and supports continued incorporation of functional capacity in preoperative evaluations.
What You Should Know
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Lower self-reported functional capacity (MET level) is strongly linked to higher 30- and 365-day mortality after noncardiac surgery.
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Mortality risk rises in a graded, dose-dependent pattern across decreasing MET categories.
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Patients with poor MET scores also experience fewer days alive and at home within one year of surgery.
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Granular MET classification provides superior risk assessment compared with traditional binary cutoffs.
Thank you to Anesthesiology for publishing this large-scale cohort study confirming the predictive power of self-reported functional capacity for surgical outcomes.