Simplified Frailty Index as a Predictor of Adverse Outcomes in Total Hip and Knee Arthroplasty

Background: The modified frailty index (mFI) has been shown to predict adverse outcomes in multiple nonorthopedic surgical specialties. This study aimed to assess whether mFI is a predictor of adverse events in patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods: Patients who underwent THA and TKA from 2005-2012 were identified in the National Surgical Quality Improvement Program database. mFI was calculated for each patient using 15 variables found in National Surgical Quality Improvement Program. Bivariate and multivariate analyses of postoperative adverse events, including Clavien-Dindo grade IV complications, were performed. Results: A total of 14,583 THA and 25,223 TKA patients were included for analysis. The mean (standard deviation, range) mFIs were 0.083 (0.080, 0-0.55) for THA and 0.097 (0.080, 0-0.64) for TKA cohorts. On bivariate analyses, incidence of Clavien-Dindo grade IV complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), hospital-acquired conditions (surgical site infection, venous thromboembolism, and urinary tract infection), any complications, and mortality increased significantly with increase in mFI (P < .0001 for all). Adjusting for demographics, age >= 75, body mass index >= 40, American Society of Anesthesiologists class >4, and nonclean wound status, mFI >0.45 was shown to be the strongest independent predictor of Clavien-Dindo grade IV complications for both THA and TKA cohorts with odds ratios of 5.140 and 4.183, respectively. Conclusion: mFI >= 0.45 is an independent predictor of Clavien-Dindo grade IV complications in TKA/THA patients with greater odds ratios than age >75, body mass index >= 40, American Society of Anesthesiologists class >= 4. mFI should be considered for risk stratifying joint arthroplasty patients preoperatively and perhaps determining immediate postoperative destination. (C) 2016 Published by Elsevier Inc.