Impact of preoperative prognostic nutritional index on postoperative in-hospital falls after surgery for cervical myelopathy: a retrospective cohort study in Japan

Study Design: Retrospective cohort study. Purpose: To investigate the association between preoperative nutritional status and postoperative in-hospital falls in patients undergoing surgery for cervical myelopathy. Overview of Literature: In-hospital falls are common adverse events among surgical patients; however, the association between preoperative nutritional indices and postoperative in-hospital falls in patients undergoing spinal surgery for cervical myelopathy remains unclear. Methods: We retrospectively reviewed clinical, laboratory, and surgical data of 649 patients who underwent surgery for cervical myelopathy at a single institution. Additionally, preoperative nutritional indices were assessed using the prognostic nutritional index (PNI), geriatric nutritional risk index, and controlling nutritional status score. Multivariable logistic regression and Cox proportional hazards regression analyses were performed to identify fall-related independent risk factors. Kaplan-Meier analysis was used to compare fall-free probability during hospitalization according to the PNI category. Results: Among 649 patients, 48 (7.4%) experienced postoperative in-hospital falls. Patients who experienced falls had significantly lower nutritional status. PNI showed the strongest association with falls among the evaluated nutritional indices (odds ratio [OR], 0.91; p <0.001) and the highest predictive performance, although its discriminatory ability was modest (area under the curve=0.687). A PNI value of <50 (OR, 3.74; p =0.001) and cerebrovascular disease (OR, 5.22; p <0.001) were identified as independent risk factors of falls; this was confirmed in the Cox analysis (PNI <50: hazard ratio [HR], 3.11; p =0.008; cerebrovascular disease: HR, 4.82; p <0.001). Conclusions: Preoperative PNI is a practical laboratory-based marker for identifying patients at high risk of postoperative falls, with low preoperative PNI (<50) associated with an increased risk of postoperative in-hospital falls in patients undergoing surgery for cervical myelopathy.