Geriatric Nutritional Risk Index as a Predictor of Outcomes After Spinal Deformity Surgery in Elderly Patients

Study DesignRetrospective cohort study.ObjectivesThe Geriatric Nutritional Risk Index (GNRI) is widely applied to evaluate malnutrition in older adults, yet its relevance in spinal deformity surgery is unclear. This study examined the relationship between nutritional status before surgery, as assessed by GNRI, and postoperative outcomes in geriatric patients undergoing spinal deformity surgery.MethodsThe 2008-2023 ACS-NSQIP database was queried for patients aged ≥65 years who underwent spinal deformity surgery. Patients were stratified by GNRI score: normal (>98), malnourished (92-98), or severely malnourished (<92). The independent association and predictive value of GNRI were assessed in comparison to the 5-item modified Frailty Index (mFI-5) and chronological age for perioperative outcomes, including length of stay, non-home discharge, and 30-day postoperative complications.ResultsA total of 2186 patients were included: 1705 (78%) had normal nutrition, 332 (15.2%) were malnourished, and 149 (6.8%) were severely malnourished. Malnourished status was independently associated with significantly greater odds of wound disruption (OR 3.3, P = .014), prolonged mechanical ventilation (OR 2.2, P = 0.019), postoperative transfusion (OR 1.5, P = .001), increased transfusion volume (coefficient 0.452, P = .044), and non-home discharge (OR 1.6, P < .001) compared to normal patients. In receiver operating characteristic analyses, GNRI demonstrated superior discriminatory ability compared with mFI-5 (P = 0.394, P = .645, P = .179, P = .113, P = .014, P = .233) and age (P = .277, P = .074, P = .039, P = .167, P < .001, P < .001) for predicting wound disruption, superficial surgical site infection, prolonged mechanical ventilation, unplanned intubation, the need for transfusion, and prolonged hospitalization.ConclusionsPreoperative malnutrition, defined by GNRI, is correlated with a greater risk of adverse outcomes following spinal deformity surgery in older adults, highlighting the importance of incorporating nutritional assessment into preoperative evaluation in this population.