The utilization of hypoalbuminemia as a prognostic metric in patients with spinal metastases: A scoping review.

Introduction: Hypoalbuminemia is associated with poor outcomes in cancer patients, but its role in spinal metastases remains unclear. Research question: This study aimed to identify albumin cutoff values defining hypoalbuminemia and describe the association between serum albumin and outcomes in patients with spinal metastases. Material and methods: A narrative review of articles up to December 2022 was conducted using PubMed/Medline, EMBASE, and Web of Science databases. Variables extracted included study design, patient characteristics, serum albumin levels, treatments, and levels of evidence. Outcomes included survival/mortality, complications, ambulatory status, readmission, length of stay, discharge disposition, and blood loss. Results: Thirty-eight studies comprising 21,401 patients were analyzed. Most studies (92%) were Level of Evidence III. Albumin was evaluated as a continuous variable in 18% of studies and as a dichotomous variable in 76%, with 3.5 g/dL being the most common threshold for hypoalbuminemia. Primary outcomes evaluated were survival/mortality (71% of studies), complications (34%), and reoperation/readmission (11%). Of studies examining the association between hypoalbuminemia and survival/mortality, 74% found a significant association. An association between albumin levels and complications was found in 54% of relevant studies. Discussion and conclusion: The findings of this study suggest that a threshold of 3.5 g/dL seems most appropriate to define hypoalbuminemia in patients with spinal metastases. However, evidence also supports a level-dependent effect. The most consistent significant association was between low albumin and survival at both fixed and continuous time points. There is less evidence to support an association between hypoalbuminemia and other endpoints such as perioperative complications.