Resident Physician University of New Mexico Albuquerque, NM, US
Introduction: The Risk Analysis Index (RAI) is a quantitatively robust frailty index recently recalibrated and validated for calculation in administrative databases and the clinical setting. The aim of this study was to evaluate the prognostic utility of baseline RAI score for prediction of postoperative outcomes after surgery for malignant spinal tumors using a large national registry.
Methods: Patients with surgically treated metastatic spinal tumors were queried from the NSQIP (2011-2020) using a combination of Current Procedural Terminology (CPT) codes and International Classification for Disease (ICD), 9th and 10th Revision, Clinical Modification codes. The association between preoperative RAI score and postoperative outcomes was assessed using proportional trend tests and area under the receiver operating characteristic (ROC) curve analysis.
Results: Among 2235 patients undergoing surgery for malignant spinal tumors, 507 were RAI 0-20, 266 were RAI 21-30, 1222 were RAI 31-40, and 240 were RAI 41+. There were 181 major complication occurrences (8.1%), 126 CD IV occurrences (5.6%), 937 NHDs (42%), 571 eLOS (26%), and 136 mortalities within 30-days (6.1%). Increasing RAI score (in stepwise 5-point bins) was statistically significantly associated with increasing rate of major complication, CD IV, eLOS, NHD, and 30-day mortality (all P< 0.05). RAI demonstrated robust discriminatory accuracy for prediction of 30-day mortality in ROC analysis (C-statistic: 0.717, 95% CI: 0.697-0.735). On pairwise ROC comparison, RAI score had statistically better discriminatory accuracy compared to modified frailty index-5 (mFI-5) and chronological age (both P< 0.001, DeLong test).
Conclusion : The burden of frailty-associated risk is significant in patients with malignant spinal tumors necessitating meticulous preoperative risk stratification and patient counseling. This was the first study to link baseline frailty (quantified by RAI score) to outcomes after surgery for malignant spinal tumors. RAI score demonstrated discriminatory superiority for 30-day mortality (vs. age and mFI-5 score) and thus warrants further attention as a neurosurgical frailty index.
