Discriminatory Value of the Risk Analysis Index Versus the 5-Factor Modified Frailty Index for Major Outcome Measures in Degenerative Cervical Myelopathy

Study DesignObservational Retrospective Cohort Study.ObjectivesTo compare the discriminatory abilities of the Revised Risk Analysis Index (RAI-Rev) and the 5-Factor Modified Frailty Index (mFI-5) to predict major postoperative outcomes in DCM patients overall, and by anterior (ADF) or posterior (PDF) approaches for decompression and fusion.MethodsThe American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for DCM patients undergoing ADF or PDF from 2015-2020. Logistic regression and Receiver Operating Characteristic analysis were used to compare the predictive and discriminatory value of mFI-5 and RAI-Rev for 30-day outcomes.Results18,138 DCM patients were included (median age: 61 years). Both RAI-Rev and mFI-5 predicted 30-day outcomes; however, increasing frailty as measured by RAI-Rev demonstrated greater odds ratios. RAI-rev demonstrated superior discrimination for non-fatal adverse outcomes, notably non-home discharge (NHD) [C-statistic 0.72 (95% CI 0.71-0.73, <i>P</i> < 0.001)], and for all non-fatal measures except major complications (<i>P</i> < 0.05). Sub-analysis by approach showed frailty had greater predictive accuracy for adverse outcomes in ADF compared to PDF.ConclusionsThe RAI-Rev demonstrated superior discrimination predicting non-fatal outcomes following DCM when compared to the mFI-5, with equivalent mortality prediction. Further, frailty plays a stronger role in predicting mortality and morbidity in ADF compared to frailty's impact on predicting outcomes with PDF. This finding demonstrates the utility of the RAI-Rev in preoperative risk stratification with an increasingly frail patient population and provides initial evidence for selecting posterior approaches for DCM patients as frailty increases.