Predictive value of six nutrition biomarkers in oncological spine surgery: a performance assessment for prediction of mortality and wound infection

OBJECTIVE Assessment of nutritional status is fundamental in cancer patients. The objective of this study was to assess the predictive ability of 6 nutritional biomarkers for postoperative mortality and wound infection after metastatic spinal tumor surgery. METHODS A total of 139 patients who underwent oncological surgery for metastatic spine disease between April 2012 and August 2022 and had a minimum follow-up of 90 days were included. Six unique nutritional biomarkers were assessed: Prognostic Nutritional Index (PNI), Nutritional Risk Index (NRI), Controlling Nutritional Status Score (CONUT), total psoas cross-sectional area (TPA), body mass index (BMI), and body weight. Study endpoints were 90-day mortality rate, 12-month mortality rate, and wound infection. The discriminative ability of each of these markers was assessed with the c-statistic. A multivariate analysis was done for each of the biomarkers after a univariate analysis was first performed. RESULTS The 90-day mortality rate was 27% (37 of 139). The biomarkers and respective c-statistics were as follows: PNI (0.74), NRI (0.75), CONUT (0.71), TPA (0.64), BMI (0.59), and body weight (0.60). The 12-month mortality rate was 56% (51 of 91). The biomarkers and respective c-statistics were as follows: PNI (0.72), NRI (0.73), CONUT (0.70), TPA (0.63), BMI (0.59), and body weight (0.60). The wound infection rate was 8% (11 of 139). The biomarkers and respective c-statistics were as follows: PNI (0.57), NRI (0.53), CONUT (0.55), TPA (0.57), BMI (0.48), and body weight (0.52). The PNI, NRI, and CONUT all predicted 90-day and 12-month mortality after multivariate regression analysis. No association between nutrition and wound infection was found. CONCLUSIONS In this study, nutritional status was associated with postoperative mortality following oncological spine surgery. Three biomarkers predicted outcome independent of variables such as performance status or primary cancer. Future validation of these metrics is needed.