Abstract
OBJECTIVE: In an aging population, patients undergoing thyroidectomy and parathyroidectomy are at an increased risk of adverse outcomes; thus, measuring patient frailty is a key metric to assess risk. This study innovatively compares the utility of the Risk Analysis Index (RAI) with the 5-factor Modified Frailty Index (mFI-5) in predicting adverse postoperative outcomes. STUDY DESIGN: Retrospective cohort. SETTING: US hospitals. METHODS: Patients undergoing thyroidectomy or parathyroidectomy procedures were selected from the 2005 to 2020 NSQIP data set. RAI and mFI-5 frailty scores were calculated and stratified: non-frail (RAI: <21/mFI-5: <1), pre-frail (RAI: 21-30/mFI-5: 1), frail (RAI: 31-40/mFI-5: 2), and severely frail (RAI: 40+/mFI-5: 3-5) categories. Univariate and multivariate analyses were conducted, followed by receiver operating characteristic (ROC) curves, to evaluate the comparative discriminative thresholds of the indices. RESULTS: A cohort of 30,362 patients was identified with a median age of 56 years. Multivariate odds ratios showed that both indices were significant independent predictors of mortality (RAI: 15.508, P < .001; mFI-5: 10.713, P < .001), extended length of stay (eLOS) (RAI: 9.480, P < .001; mFI-5: 7.952, P < .001), non-home discharge (RAI: 15.897, P < .001; mFI-5: 9.346, P < .001), and Clavien-Dindo (CD) II complications (RAI: 7.130, P < .001; mFI-5: 3.760, P < .001). ROC analysis demonstrated significantly superior discrimination by the RAI for mortality (0.769 vs 0.650, P = .022), eLOS (0.712 vs 0.596, P < .001), non-home discharge (0.763 vs 0.639, P < .001), CD II (0.739 vs 0.566, P < .001), CD IIIb (0.644 vs 0.587, P = .002), CD IV (0.707 vs 0.622, P < .001), and organ/space infection (0.719 vs 0.519, P < .001). CONCLUSION: Both the RAI and mFI-5 frailty indices are comparable, significant predictors of adverse events in thyroidectomy/parathyroidectomy. The RAI demonstrated superior discrimination for predicting postoperative morbidity across most outcomes, indicating it may be a superior clinical tool for identifying high-risk patients. The RAI may better inform perioperative decision-making, patient counseling, and resource allocation.