Predicting 30-day mortality after surgery for metastatic disease of the spine: the H2-FAILS score

Abstract

Purpose: Scoring systems for metastatic spine disease focus on predicting long- to medium-term mortality or a combination of perioperative morbidity and mortality. However, accurate prediction of perioperative mortality alone may be the most important factor when considering surgical intervention. We aimed to develop and evaluate a new tool, the H₂-FAILS score, to predict 30-day mortality after surgery for metastatic spine disease.

Methods: Using the National Surgical Quality Improvement Program database, we identified 1195 adults who underwent surgery for metastatic spine disease from 2010 to 2018. Incidence of 30-day mortality was 8.7% (n = 104). Independent predictors of 30-day mortality were used to derive the H₂-FAILS score. H₂-FAILS is an acronym for: Heart failure (2 points), Functional dependence, Albumin deficiency, International normalized ratio elevation, Leukocytosis, and Smoking (1 point each). Discrimination was assessed using area under the receiver operating characteristic curve (AUC). The H₂-FAILS score was compared with the American Society of Anesthesiologists Physical Status Classification (ASA Class), the 5-item modified Frailty Index (mFI-5), and the New England Spinal Metastasis Score (NESMS). Internal validation was performed using bootstrapping. Alpha = 0.05.

Results: Predicted 30-day mortality was 1.8% for an H₂-FAILS score of 0 and 78% for a score of 6. AUC of the H₂-FAILS was 0.77 (95% confidence interval: 0.72-0.81), which was higher than the mFI-5 (AUC 0.58, p < 0.001), ASA Class (AUC 0.63, p < 0.001), and NESMS (AUC 0.70, p = 0.004). Internal validation showed an optimism-corrected AUC of 0.76.

Conclusions: The H₂-FAILS score accurately predicts 30-day mortality after surgery for spinal metastasis.

Level of evidence: Prognostic level III.

Keywords: Metastasis; Mortality; Outcomes; Prediction; Score; Spine tumor.