The effect of adding functional classification to ASA status for predicting 30-day mortality

Area of Science:

• Anesthesiology
• Perioperative Medicine
• Public Health

Background:

• Functional capacity is a known predictor of perioperative mortality.
• Current American Society of Anesthesiologists (ASA) classification does not formally include functional capacity.
• Assessing functional capacity could refine preoperative risk stratification.

Purpose of the Study:

• To determine if functional capacity is an independent predictor of 30-day and long-term mortality.
• To explore incorporating functional capacity into the ASA classification system.

Main Methods:

• Retrospective cohort study (1998-2009) of 12,324 patients undergoing noncardiac surgery.
• Modified ASA classification by adding subclasses A (independent) and B (dependent).
• Multivariate logistic regression analyzed all-cause mortality and 30-day postoperative outcomes.

Main Results:

• Functionally independent (A) patients had significantly lower mortality than dependent (B) patients within each ASA class.
• Modified ASA classification improved the prediction of 30-day mortality by 4.7% (AUC 0.848 vs. 0.811).
• Odds ratios for mortality favored survival in group A patients across ASA classes II, III, and IV.

Conclusions:

• Functional capacity is an independent predictor of mortality within ASA classes.
• Consideration for incorporating functional dependence into ASA classification is recommended.
• Prospective validation is needed to confirm findings and guide clinical practice.