Predictive value of hypoalbuminemia and severe hypoalbuminemia in oncologic spine surgery

Study design: Retrospective review of a prospectively collected national database. Objective: To evaluate the predictive value of hypoalbuminemia on outcomes in surgical spine oncology patients. Summary of background data: It is well documented that patients with hypoalbuminemia (albumin <3.5) have significantly higher rates of surgical morbidity and mortality than patients with normal albumin (>3.5 g/dl). We evaluated outcomes for metastatic oncologic spine surgery patients based on pre-operative albumin levels. Materials and methods: Patients who underwent surgery for metastatic spine disease were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2006 to 2016. Three groups were established: patients with normal albumin (>3.5 g/dl), mild hypoalbuminemia (2.6 g/dl – 3.4 g/dl), and severe hypoalbuminemia (<=2.5 g/dl). A multivariate analysis was used to assess the association between albumin levels and mortality within 30 days of surgical intervention. Results: A total of 700 patients who underwent surgery for metastatic spinal disease and had pre-operative albumin levels available were identified; 64.0% had normal albumin (>3.5 g/dl), 29.6% had mild hypoalbuminemia, and 6.4% had severe hypoalbuminemia. The overall 30-day mortality was 7.6% for patients with normal albumin, 15.9% for patients with mild hypoalbuminemia, and 44.4% for patients with severe hypoalbuminemia. On multivariate analysis, patients with mild hypoalbuminemia (OR 1.7 95% CI: 1.0–3.0 p = 0.05) and severe hypoalbuminemia (OR 6.2 95% CI: 2.8–13.5 p < 0.001) were more likely to expire within 30 days compared to patients with preoperative albumin above 3.5 g/dl. Conclusion: In this study, albumin level was found to be an independent predictor of 30-day mortality in patients who underwent operative intervention for metastatic spinal disease. Patients with severe hypoalbuminemia had a 7-fold increased risk when compared with those who had normal albumin.