Baseline Frailty and Discharge to Advanced Care Facilities in Patients Undergoing Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Multicenter Registry Analysis of 7153 Patient Cases Comparing the Risk Analysis Index to the 5-Factor Modified Frailty Index

Abstract

Objective: To evaluate the impact of frailty, as measured by the 5-factor modified Frailty Index (mFI-5) and the Risk Analysis Index (RAI), on advanced care facility discharge (FD) in patients who underwent lumbar fusion for lumbar degenerative spine disease.

Methods: The American College of Surgeons National Surgical Quality Improvement Program (2012-2020) was queried for adults (≥18 years) undergoing lumbar fusion for lumbar degenerative disease. Descriptive statistics and univariate crosstabulation were used to assess baseline demographics, preoperative comorbidities, and postoperative outcomes. Receiver operating characteristic curve analysis was used to assess the discriminative threshold of the mFI-5 and RAI on FD within this population.

Results: The median patient age in this study cohort (N = 7153) was 56 years and FD occurred in 7.3% of cases. Receiver operating characteristic curve analysis demonstrated that both the mFI-5 and the RAI accurately predicted FD (C-statistics: mFI-5: 0.627; RAI: 0.746). DeLong's test found that the RAI had superior discrimination when compared to the mFI-5 (P < 0.0001).

Conclusions: RAI is a reliable predictor of FD in lumbar degenerative disease patients who underwent lumbar interbody fusion and demonstrated superior discrimination compared to the mFI-5. Identification of patients at risk for FD may facilitate more precise risk stratification to enable better preoperative decision-making and help set more realistic expectations of care.

Keywords: 5-Factor modified frailty index; Degenerative; Frailty; Lumbar spine; National surgical quality improvement program; Risk analysis index; Spine fusion.