Association of Preoperative Red Cell Distribution Width with Postoperative Outcomes in Liver Transplantation Recipients

Abstract

Background: The 1-year mortality rate after liver transplantation is approximately 8%-20%. It is important to explore risk factors associated with postoperative outcomes in liver transplantation recipients (LTRs). Red cell distribution width (RDW) is an indicator that assesses the variability in the volume of red blood cells in circulation. RDW is not only related to inflammatory levels and nutritional status but also associated with postoperative outcomes in surgical patients. However, the relationship between preoperative RDW and postoperative outcomes in LTRs remains unclear. Therefore, we designed a retrospective observational study to investigate the impact of preoperative RDW levels on postoperative outcomes in LTRs. Methods: We retrospectively collected clinical data of patients who underwent allogeneic liver transplantation at West China Hospital, Sichuan University, from January 2016 to December 2020. The primary outcome was 1-year mortality. Secondary outcomes included 30-day mortality, long-term survival, early postoperative graft dysfunction, acute kidney injury, renal replacement therapy, pulmonary complications, duration of postoperative mechanical ventilation, length of ICU stay, and length of hospital stay. Patients were divided into two groups: RDW ≤ 14.5% and RDW > 14.5%. We selected 14 covariates and used propensity score matching (PSM) to adjust for baseline characteristics. Postoperative outcomes and long-term survival were analyzed after PSM. Receiver operating characteristics (ROC) curves and subgroup analyses were also performed. Results: A total of 661 patients who underwent liver transplantation surgery were screened for this study. Finally, 438 patients were included in the statistical analysis. After PSM, there were no statistically significant differences in postoperative mortality and complications between the RDW ≤ 14.5% group and the RDW > 14.5% group (P > 0.05). The comparison of long-term survival between the two groups also showed no statistical difference (hazard ratio = 0.67, 95% confidence interval: 0.28-1.61, P = 0.358). Subgroup analyses showed consistent results. The ROC curve indicated that the predictive ability of preoperative RDW levels for 1-year mortality is moderate (area under the ROC curve 0.661). Conclusion: Preoperative RDW levels do not affect postoperative mortality and the incidence of complications in LTRs. However, these results still need further research for verification.