Impact of Preoperative Malnutrition on Postoperative Quality of Life in Older Adults Undergoing Surgery for Degenerative Cervical Myelopathy: A Retrospective Cohort Study

<b>Background/Objectives:</b> Malnutrition, which is closely associated with frailty and sarcopenia, is common in older adults and is linked to adverse perioperative complications in musculoskeletal surgery. However, its influence on postoperative health-related quality of life (HRQOL) remains unclear. This study aimed to investigate the impact of preoperative malnutrition on HRQOL one year after surgery in elderly patients with degenerative cervical myelopathy (DCM). <b>Methods:</b> We retrospectively analyzed 188 patients aged ≥ 65 years who underwent elective surgery for DCM between 2017 and 2024. Preoperative nutritional status was assessed using the Geriatric Nutritional Risk Index (GNRI), with GNRI ≤ 98 indicating malnutrition risk. Patient-reported outcome measures were assessed using the EuroQol Five-Dimension Questionnaire (EQ-5D) both preoperatively and at one year postoperatively. The minimum clinically important difference (MCID) threshold was applied to evaluate significant changes. Multivariate logistic regression was used to identify independent risk factors for postoperative deterioration in EQ-5D score. <b>Results:</b> Of the 188 patients, 35 were classified as having malnutrition risk. While preoperative EQ-5D scores were comparable between the two groups, the postoperative EQ-5D score was significantly lower in the malnutrition risk group than in the no-risk group (0.58 vs. 0.67, <i>p</i> = 0.003). Deterioration in EQ-5D scores exceeding the MCID threshold occurred more frequently in the malnutrition risk group (37.1% vs. 21.2%, <i>p</i> = 0.049). Furthermore, multivariate analysis identified preoperative GNRI ≤ 98 as an independent risk factor for deterioration in EQ-5D score exceeding the MCID threshold (OR 2.40, 95% CI 1.03-5.52). <b>Conclusions:</b> Preoperative malnutritional status was significantly associated with impaired postoperative HRQOL in elderly patients with DCM. These findings highlight the need for preoperative nutritional assessment and optimization in this vulnerable population.