A Retrospective Cohort Study Examining the Validation of the Modified Duke Activity Status Index in the Non-cardiac Surgical Population.

Purpose: We aimed to ascertain if the Duke Activity Status Index (DASI) and its simplified variants predict 30-day mortality and myocardial injury after major non-cardiac surgery in at-risk patients.

Design: Retrospective cohort study.

Methods: We included 4,199 patients to validate the DASI and its variants in predicting the same composite outcome in patients with risk factors for coronary artery disease. Additional outcomes included 30-day severe complications, 1-year survival, and the effect of the Area Deprivation Index (ADI) on the DASI score and subsequent outcomes.

Findings: Patients were a median of 66 years old (interquartile range 57.0, 73.0), 47.9% were male, predominantly Caucasian (71.9%), with an American Society of Anesthesiologists score of 3 or greater (80.7%) and a median National ADI of 54.0 (interquartile range 33.0 to 74.0). The 30-day composite outcome was predicted by the original DASI (area under the curve [AUC] 0.82 [CI 0.73, 0.91], P < .001); modified 4-question DASI (AUC 0.82 [CI 0.73, 0.91], P < .048). The original DASI also predicted the 1-year composite outcome (hazard ratio 0.88 [CI 0.84, 0.93], P < .001), as did the modified 4-question DASI (hazard ratio 0.78 [CI 0.69, 0.89], P < .001), but not severe complications (P = .400 and P = .332 respectively). The ADI showed an inverse relationship with all versions of the DASI; there was a 0.8-point DASI decrease ([95% confidence interval -0.96 to -0.59], P < .001) for every 10-point increase in the National ADI.

Conclusions: The DASI is a reliable predictor of long-term postoperative outcomes.