5-Item Modified Frailty Index Predicts Outcomes After Below-Knee Amputation in the Vascular Quality Initiative Amputation Registry
James C. Andersen, Joshua Gabel, Kristyn Mannoia, Sharon C. Kiang, Sheela T. Patel, Theodore H. Teruya, Christian Bianchi, Ahmed M. Abou‐Zamzam
Abstract
Patient frailty indices are increasingly being utilized to anticipate post-operative complications. This study explores whether a 5-factor modified frailty index (mFI-5) is associated with outcomes following below-knee amputation (BKA). All BKAs in the vascular quality initiative (VQI) amputation registry from 2012-2017 were reviewed. Preoperative frailty status was determined with the mFI-5 which assigns one point each for history of diabetes, chronic obstructive pulmonary disease or active pneumonia, congestive heart failure, hypertension, and nonindependent functional status. Outcomes included 30-day mortality, unplanned return to odds ratio (OR), post-op myocardial infarction (MI), post-op SSI, all-cause complication, revision to higher level amputation, disposition status, and prosthetic use. 2040 BKAs were performed. Logistic regression showed an increasing mFI-5 score that was associated with higher risk of combined complications (OR 1.22, confidence interval [CI] 1.07-1.38, P < .05), 30-day mortality (OR 1.60, CI 1.19-2.16, P < .05), post-op MI (OR 1.79, CI 1.30-2.45, P < .05), and failure of long-term prosthetic use (OR 1.17, CI 1.03-1.32, P < .05). In the VQI, every one-point increase in mFI-5 is associated with an increased risk of 22% for combined complications, 60% for 30-day mortality, nearly 80% for post-op MI, and 17% for failure of prosthetic use in BKA patients. The mFI-5 frailty index should be incorporated into preoperative planning and risk stratification.