INTRODUCTION: Although frailty has been recognized to adversely influence outcomes of emergency general surgery, there are limited data comparing the performance of frailty instruments among this population. We compared the discriminatory power of 4 risk prediction models across a national cohort of patients who underwent emergency general surgery to assess outcomes of interest. METHODS: Adults undergoing emergency general surgery (large bowel resection, small bowel resection, repair of perforated ulcer, cholecystectomy, appendectomy, lysis of adhesions, or laparotomy) were identified in 2016-2021 Nationwide Readmissions Database. Patients were grouped into frail and non-frail cohorts on the basis of various frailty instruments: Hospital Frailty Risk Score, Modified 5-factor Frailty Index, Modified 11-factor Frailty Index, and Johns Hopkins Adjusted Clinical Groups index. Multivariable regressions were developed to assess independent associations between frailty instruments and in-hospital mortality as well as a composite of perioperative complications. RESULTS: Of 1,385,505 hospitalizations for emergency general surgery, 57.0%, 29.9%, 26.6%, and 10.5% were identified as frail by mFI-11, Hospital Frailty Risk Score, Modified 5-factor Frailty Index, and Adjusted Clinical Groups, respectively. After multivariable adjustment, Hospital Frailty Risk Score demonstrated the greatest discriminatory power for predicting in-hospital mortality and perioperative complications when compared with other frailty indices. Subjects classified as frail using the Hospital Frailty Risk Score were associated with the greatest risk of mortality (adjusted odds ratio, 7.8
95% confidence interval, 7.4-8.3) and composite complications (adjusted odds ratio, 8.4
95% confidence interval, 9.3-8.5) compared with other indices across all frailty levels. CONCLUSION: Among patients undergoing emergency general surgery, Hospital Frailty Risk Score demonstrated the greatest discrimination in predicting mortality and composite complications. Risk-stratification efforts should prioritize Hospital Frailty Risk Score in elderly patients undergoing emergency general surgery to optimize clinical outcomes and resource allocation.