The Geriatric Nutritional Risk Index Is an Independent Predictor for Adverse Outcomes After Anterior Cervical Discectomy and Fusion

Malnutrition has frequently been associated with increased complications and worse outcomes after surgery. The purpose of this study was to determine if malnutrition status determined using the Geriatric Nutritional Risk Index (GNRI) serves as an independent risk factor for complications in patients undergoing anterior cervical discectomy and fusion (ACDF). The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2011 to 2016 for patients aged ≥65 years who underwent ACDF. Patients were categorized into 3 groups based on the GNRI: >98 were normal nutritional status, 92-98 were moderately malnourished, and <92 were severely malnourished. Multivariate logistic regression models adjusted for covariates of demographics, comorbidities, and operative metrics were used to evaluate GNRI as an independent risk factor for postoperative outcomes. 3,148 patients who underwent ACDF were analyzed, of which 78.9% had normal nutrition, 16.1% were moderately malnourished, and 5.0% patients were severely malnourished. On multivariate analysis, moderate and severe malnutrition were found to be independent risk factors for any complication, pulmonary complications, pneumonia, unplanned intubation, and hospital length of stay >6 days (all, p<0.05). In addition, moderate malnutrition was a risk factor for failure to wean from ventilator >48 hours and 30-day readmission. Severe malnutrition was an independent risk factor for septic-shock and non-home discharge. In elderly patients after ACDF, malnutrition determined using GNRI is an independent risk factor for 30-day complications, readmissions, prolonged hospital length of stays, and non-home discharge.