Frailty Syndrome in Patients with Carotid Disease: Simplifying How We Calculate Frailty

Background: Frailty syndrome is an established predictor of adverse outcomes after carotid surgery. Recently, a modified 5-factor National Surgical Quality Improvement Program frailty index has been used; however, its utility in vascular procedures is unclear. The aim of our study was to compare the 5-factor modified frailty index (mFI-5) with the 11-factor modified frailty index (mFI-11) regarding 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 rho test was used to assess the correlation between the mFI-5 and mFI-11. Predictive models, using both unadjusted and adjusted logistic regressions, were created for each outcome for carotid endarterectomy using 2005-2012 National Surgical Quality Improvement Program data, the last year all mFI-11 variables existed. Results: A total of 36,000 patients were included with mean age of 74.6 +/- 5.9 years, complication rate of 10.7%, mortality rate of 3.1%, and readmission rate of 6.2%. Correlation between mFI-5 and mFI-11 was above 0.9 across all outcomes for patients. mFI-5 had strong predictive ability for mortality, postoperative complications, and 30-day readmission. Conclusions: The mFI-5 and mFI-11 are equally effective predictors of postoperative outcomes in patients undergoing carotid endarterectomy. mFI-5 is a strong predictor of postoperative complications, mortality, and 30-day readmission.