Assessing combined effects of risk analysis index-revised (RAI-rev), malnutrition, and anemia on morbidity and mortality after spine surgery for metastatic spinal tumors.

PURPOSE

This study evaluates the combined effects of frailty, anemia, and malnutrition on outcomes in spinal metastases patients.

METHODS

We conducted a retrospective cohort study using the 2011-2022 NSQIP database. Adult patients undergoing spinal surgery for spinal metastases were identified using CPT and ICD codes and stratified based on Risk Analysis Index-revised (RAI-rev) frailty status; frail patients were subdivided based on anemia and malnutrition status. Our primary outcomes were extended hospital length of stay (LOS), 30-day adverse events (AEs), non-routine discharge (NRD), and 30-day mortality. For each outcome, we fitted four nested multivariable logistic regression models (RAI-rev + anemia + malnutrition, RAI-rev + anemia, RAI-rev + malnutrition, and RAI-rev alone) and compared the incremental discrimination of each model using receiver operating characteristic (ROC) analysis.

RESULTS

1530 patients were stratified accordingly: 355 Frail Alone, 540 Frail + Anemic, 85 Frail + Malnourished, 407 Frail + Anemic + Malnourished, and 143 Not Frail. RAI-rev and malnourishment were risk factors for extended LOS ((RAI-rev: aOR 1.04, 95% CI 1.01-1.08; malnourishment: aOR 1.98, 95% CI 1.44-2.73)) and mortality (RAI-rev: aOR: 1.07, 95% CI 1.03-1.11; malnourishment: aOR: 2.37, 95% CI 1.50-3.75). RAI-rev (aOR 1.02, 95% CI 1.00-1.03) and anemia (aOR 2.06, 95% CI 1.50-2.84) independently predicted AEs and malnourishment predicted NRD (aOR 1.56, 95% CI 1.15-2.13). On ROC analysis, RAI-rev + anemic + malnourished superiorly predicted extended LOS (p = 0.021), AEs (p = 0.035), and mortality (p = 0.023) compared to RAI-rev. RAI-rev + malnourished outperformed RAI-rev in predicting extended LOS (p = 0.035) and mortality (p = 0.020). RAI-rev + anemic outperformed RAI-rev in predicting AEs (p = 0.032).

CONCLUSION

Our study suggests that RAI-rev-defined frailty combined with anemia and malnutrition is a superior predictor of outcomes in spinal metastases patients.