81.05 New 5-Factor Frailty Index Can Predict Outcomes in Patients Undergoing Endovascular Aneurysm Repair

V. Pandit1, M. Zeeshan1, S. Jhajj1, A. Lee1, K. R. Goshima1, C. Weinkauf1, W. Zhou1, T. Tan1  1University Of Arizona,Department Of Surgery,Tucson, AZ, USA

Introduction:
The modified frailty index (mFI-11) is a NSQIP-based 11-factor index that has been proven to adequately reflect frailty and predict mortality and morbidity. In past years, certain NSQIP variables have been removed from the database; as of 2015, only 5 of the original 11 factors remained. The predictive power and usefulness of these 5 factors in an index (mFI-5) have not been proven in patients undergoing endovascular repair (EVAR) of abdominal aortic aneurysm (AAA). The goal of our study was to compare the mFI-5 to the mFI-11 in terms of value and predictive ability for mortality, postoperative infection, and unplanned 30-day readmission.

Methods:
The mFI was calculated by dividing the number of factors present for a patient by the number of available factors for which there were no missing data. Spearman's rho test was used to assess correlation between the mFI-5 and mFI-11. Predictive models, using both unadjusted and adjusted logistic regressions, were created for each outcome for EVAR using 2005-2012 NSQIP data, the last year all mFI-11 variables existed.

Results:
A total of 14,387 patients were included. Mean age was 71.6±6.5. Overall, 22.1% patients were frail. A total of 24.1% had in-hospital complications, while 4.9% patients died. Correlation between the mFI-5 and mFI-11 was above 0.9 across all outcomes for patients undergoing EVAR. Adjusted and unadjusted models showed similar c-statistics for mFI-5 and mFI-11, and strong predictive ability for mortality, postoperative complications and 30-days readmission (Table 1).

Conclusion:
The mFI-5 and the mFI-11 are equally effective predictors of postoperative outcomes in patients undergoing endovascular aneurysm repair of abdominal aortic aneurysm and the mFI-5 is a strong predictor of postoperative complications, mortality and 30-d readmission. It has credibility for future use to study frailty within the NSQIP database. It also has potential in other databases and for clinical use.