Association of preoperative hypoprotein malnutrition with spinal postoperative complications and other conditions: A systematic review and meta-analysis

Background: Postoperative complications of spinal surgery are a common clinical problem, which impose significant economic and clinical burdens on patients and medical staff. Previous studies have suggested a close relationship between low-protein malnutrition and postoperative complications of surgery. However, the relationship between preoperative malnutrition and various orthopedic postoperative complications remains unclear. Purpose: To investigate the association between protein malnutrition and postoperative complications and outcomes. Methods: We conducted a systematic search of the PubMed, Embase, Cochrane Library, and Web of Science databases for published research articles between the database inception and February 28th, 2023, that evaluated the association between malnutrition and the risk of postoperative complications and death in spinal surgery patients. Malnutrition was defined as low pre-albumin and albumin levels before surgery. Two evaluators independently extracted study data and assessed the risk of bias in each study. Fixed- or random-effect models were used to calculate the pooled effect estimates. Funnel plots and Egger's tests were used to detect publication bias, and the Trim-and -Fill method was conducted to evaluate the impact of publication bias on the results. Results: A total of 26 studies were included in this meta-analysis, comprising 17 retrospective cohort studies and 9 case-control studies. The study included more than 86,000 participants. Analysis of postoperative complications revealed that the overall incidence of malnutrition-related complications after surgery was 3.17 times higher (OR = 3.17, 95% CI 2.69-3.75, z = 13.57, P < 0.05). The incidence of surgical site infections was 2.08 times higher (OR = 2.08, 95% CI 1.66-2.62, z = 6.307, P < 0.05), and the incidence of postoperative urinary tract infections was 2.55 times higher (OR = 2.55, 95% CI 1.80-3.60, z = 5.30, P < 0.05). The incidence of postoperative sepsis was 3.31 times higher (OR = 3.31, 95% CI 2.31 -4.75, z = 6.51, P < 0.05), and the incidence of postoperative pneumonia was 3.02 times higher (OR = 3.02, 95% CI 1.331-6.857, z = 2.64, P = 0.008 < 0.05). The incidence of postoperative cardiac complications was 4.24 times higher (OR = 4.24, 95% CI 2.45-7.35, z = 5.15, P < 0.05), and the incidence of postoperative renal complications was 4.04 times higher (OR = 4.04, 95% CI 2.06-7.93, z = 4.05, P < 0.05). The incidence of postoperative pulmonary complications was 2.38 times higher (OR = 2.38, 95% CI 1.46-3.87, z = 6.98, P < 0.05), while the incidence of postoperative thrombotic complications was 2.76 times higher (OR = 2.76, 95% CI 1.756-4.345, z = 4.40, P < 0.05). Furthermore, the incidence of transfusion during and after surgery was 1.33 times higher (OR = 1.33, 95% CI 1.13-1.56, z = 3.40, P = 0.001 < 0.05), the incidence of postoperative readmission was 1.67 times higher (OR = 1.67, 95% CI 1.24-2.27, z = 3.33, P = 0.001 < 0.05), and the risk of postoperative death was 6.01 times higher (OR = 6.01, 95% CI 4.51-8.01, z = 12.27, P < 0.05). After conducting a publication bias test and Trim-and -Fill method analysis, we found no evidence of publication bias, and the results remained stable. Conclusion: Preoperative low protein malnutrition is closely related to the incidence of postoperative complications and postoperative status. More prospective multicenter studies should be conducted to validate this conclusion. Furthermore, more effective assessment and intervention of preoperative nutritional status should be carried out to prevent the occurrence of postoperative complications and mortality risk. & COPY; 2023 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.