Is the American Society of Anesthesiologists classification useful in risk stratification for endoscopic procedures?

BACKGROUND: The American Society of Anesthesiologists (ASA) physical status classification is a measurement of comorbidity and a predictor of perioperative morbidity and mortality.

OBJECTIVE: To assess the predictive ability of the ASA class for periendoscopic adverse events.

DESIGN: Retrospective cohort analysis.

SETTING: A total of 74 sites in the United States comprising academic, community/health maintenance organization, and Veterans Affairs/military practices affiliated with the Clinical Outcomes Research Initiative (CORI) database.

PATIENTS: Patients who were 18 years or older who underwent an endoscopic procedure between 2000 and 2008.

INTERVENTIONS: EGD, colonoscopy, flexible sigmoidoscopy, and ERCP.

MAIN OUTCOME MEASUREMENTS: Immediate adverse event requiring an unplanned intervention.

RESULTS: A total of 1,590,648 endoscopic procedures were performed on 1,318,495 individual patients. The majority of patients were designated as ASA class I or II (I: 27%, II: 63%). An immediate adverse event occurred in 0.35% of all endoscopic procedures (n = 5596) and was proportionally highest for ERCPs (1.84%). Increasing ASA class was associated with higher prevalence and a stepwise increase in the odds ratio of serious adverse events for EGD (II: 1.54 [95% confidence interval (CI), 1.31-1.82]; III: 3.90 [95% CI, 3.27-4.64]; IV/V: 12.02 [95% CI, 9.62-15.01]); and colonoscopy (II: 0.92 [95% CI, 0.85-1.01]; III: 1.66 [95% CI, 1.46-1.87]; IV/V: 4.93 [95% CI, 3.66-66.3]). This trend was not significant for flexible sigmoidoscopy and ERCP.

LIMITATIONS: Retrospective; endpoint was a surrogate for periprocedure morbidity.

CONCLUSIONS: ASA class is associated with increased risk of adverse events at endoscopy, particularly for EGD and colonoscopy. It is useful in endoscopic risk stratification and an important quality indicator for endoscopy.