Albumin and Spinal Epidural Abscess: Derivation and Validation in Two Independent Data Sets

BACKGROUND: None of the existing prognostic scoring systems for spinal epidural abscess (SEA) include albumin despite albumin's established role in inflammation, nutrition, lipid peroxidation, and regulation of apoptosis. The purpose of the present study was to determine the prognostic value of albumin in SEA. METHODS: We performed a retrospective, case-control study of 2 independent data sets: patients with SEA in an institutional population and patients in the National Surgical Quality Improvement Program (NSQIP). Bivariate analyses and multivariate analyses were used to determine whether albumin is an independent prognostic factor for survival in both data sets. RESULTS: For the 1053 patients with SEA in the institutional cohort, the 90-day postdischarge mortality was 134 (12.7%). Overall, 633 (60.1%) underwent surgery in the initial admission, with a 30-day postoperative mortality rate of 5.5% (n = 35). For the 1154 patients with SEA in the NSQIP database, the 30-day postoperative mortality rate was 3.6% (n = 42). The rate of 90-day postdischarge mortality in the institutional cohort for patients with albumin <2.3 g/dL was 25.1%. In contrast, the rate for patients with albumin >3.3 g/dL was 4.5%. On multivariate analysis of the NSQIP database, hypoalbuminemia was an independent prognostic factor for 30-day postoperative mortality. On multivariate analysis of the institutional cohort, hypoalbuminemia remained a prognostic factor for 90-day postdischarge mortality. CONCLUSION: Albumin was validated as an independent prognostic factor in patients with SEA. The lack of this marker in existing scoring systems underscores the need for updated models to optimize risk stratification and shared decision-making before surgery.