A Novel Prognostic Marker in Patients Undergoing Spinal Surgery: Prognostic Nutritional Index

The relationship of a preoperative Prognostic Nutritional Index (PNI) with perioperative adverse events (PAEs) other than delirium has never been described in patients undergoing spinal surgery. We aimed to evaluate the impact of admission PNI on the outcome of patients undergoing spinal surgery.

Medical records of 408 consecutive patients 50 years or older undergoing spinal surgery were reviewed. Patients' information including demographic data, routine preoperative laboratory tests, and PNI were collected to assess the association between these factors and PAEs. The PNI was calculated from this formula: 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count/mm³. Receiver operating characteristic curve analysis was performed to determine the cutoff value of the PNI.

PAEs occurred in 61 (14.9%) of the patients. Older patients and those with more comorbid conditions such as atrial fibrillation, chronic renal failure, history of malignancy, and diabetes mellitus tended to have a higher rate of PAEs. Patients with PAEs had higher C-reactive protein (4.4 ± 5.4 vs 2.2 ± 3.0 mg/dL; p < 0.001) but had lower hemoglobin levels (12.2 ± 1.57 vs 13.1 ± 1.84 g/dL; p < 0.001) on admission. Patients who had PAEs had a significantly lower preoperative PNI (46.1 ± 4.4 vs 51.9 ± 5.8; p < 0.001) compared with patients without a PAE. Multivariate analysis showed that age (odds ratio [OR]: 1.23; 95% confidence interval [CI] 0.76-1.35; p < 0.04), PNI < 47.7 (OR: 2.51; 95% CI, 1.188-5.477; p = 0.008) and the presence of diabetes (OR: 3.23; 95% CI, 11.326-7.474; p = 0.004) were significant and independent predictors of PAEs.

This study is the first to demonstrate that a lower preoperative PNI is associated with PAEs in patients undergoing spinal surgery.