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. While these findings need to be validated by future studies, we believe they will prove useful for preoperative risk stratification and surgical decision-making.