Which Objective Nutritional Index Is Better for the Prediction of Adverse Medical Events in Elderly Patients Undergoing Spinal Surgery?

Objective: The relationship of preoperative malnutrition with perioperative adverse medical events (PAMEs) has not been well studied in elderly patients undergoing spinal surgery (SS). We aimed to compare the Prognostic Nutritional Index (PNI), Controlling Nutritional Status (CONUT) score, and Geriatric Nutritional Risk Index (GNRI) for prediction of PAMEs in elderly patients undergoing SS.

Methods: Data of 454 patients ≥65 years old undergoing SS were reviewed. PAMEs were defined as death, cardiopulmonary complications, respiratory failure, acute kidney injury, pneumonia, delirium, cerebrovascular events, and sepsis. The area under the receiver operating characteristic curve was used to compare the predictive value of each nutritional index for PAMEs.

Results: Incidence of PAMEs was 15.3%. Patients who had PAMEs had significantly lower GNRI and PNI but higher CONUT score before surgery compared with patients without PAMEs. Multivariate analysis showed that age (odds ratio [OR] 1.55, 95% confidence interval [CI] 1.01-4.75, P = 0.014), chronic renal failure (OR 1.34, 95% CI 1.03-3.82, P = 0.002), coronary artery disease (OR 1.12, 95% CI 1.11-3.54, P = 0.028), PNI <45.4 (OR 2.12, 95% CI 1.16-4.80, P = 0.011), CONUT score >5 (OR 2.17, 95% CI 1.03-3.76, P = 0.001), and GNRI <92 (OR 2.68, 95% CI 1.20-6.45, P < 0.001) were significant predictors of PAMEs. The receiver operating characteristic curve showed that GNRI had much greater discriminatory ability regarding PAMEs than PNI and CONUT score.

Conclusions: Preoperative malnutrition is associated with PAMEs in elderly patients undergoing SS. GNRI had the highest accuracy for predicting PAMEs among the nutritional indices studied.