Association of nutritional risk with postoperative functional outcomes in patients undergoing spinal surgery: a retrospective cohort study
Abstract
The role of malnutrition as a predictor of postoperative outcome after spine surgery has been increasingly recognized, although its impact on long-term functional recovery is still poorly understood. The present study aims at analyzing the relationship between malnutrition, according to malnutrition severity criteria, and postoperative functional recovery. To determine whether malnutrition before surgery is related to postoperative recovery and adverse events in elective spine surgery. A retrospective cohort analysis was conducted on 900 patients who underwent elective spinal surgery between 2020 and 2024. They were classified into four groups according to the criteria: no malnutrition ( n = 270), mild ( n = 324), moderate ( n = 198), and severe malnutrition ( n = 108). Functional outcomes were measured using ODI, VAS, EQ-5D-5L, FIM, and Barthel Index over 12 months. Multivariable logistic regression, Cox proportional hazards regression, repeated-measures ANOVA, and ROC analyses were performed. Functional recovery progressively deteriorated as malnutrition became more severe. Mean 12-month ODI score was 16.8 ± 9.4 in no-malnutrition patients, compared to 49.8 ± 15.6 in the severe malnutrition group ( p < 0.001); while MCID attainment was 90.4% vs. 63.0%. Postoperative complications occurred in 10.4% vs. 59.3% patients, major complications in 3.7% vs. 24.1% patients, and 30-day mortality occurred in 0% vs. 7.4% patients (all p < 0.001). Severe malnutrition was a strong predictor of poor functional outcome (OR = 5.64, 95% CI 3.32 to 9.58; p < 0.001) and poor functional recovery (HR = 0.46, 95% CI 0.35 to 0.60; p < 0.001). Malnutrition according to criteria is a significant predictor of poor functional recovery, postoperative complications, and length of stay after spinal surgery. Preoperative nutrition assessment and optimizing nutrition may help improve outcomes after spinal surgery.