A Systematic Review of Donor Serum Sodium Level and Its Impact on Transplant Recipients

BACKGROUND: An important aspect of donor management is the optimization of serum sodium levels. OBJECTIVE: To perform a systematic review to determine the effects of donor sodium levels on heart, lung, kidney, and pancreas graft function, recipient mortality, and to identify the optimal donor serum sodium target. METHODS: We searched MEDLINE, Cochrane, Guideline databases, and trial registries from 1946 to May 2019 for studies investigating the effects of donor serum sodium levels on transplant outcomes in all non-hepatic organs. A two-step independent review process was used to identify relevant articles based on inclusion/exclusion criteria. We describe the results narratively, assess the risk of bias, and apply GRADE methodology to evaluate the certainty in the evidence. RESULTS: We included 18 cohort studies in our final analysis (n=28,007). 3 of 4 studies demonstrated an association between donor serum sodium and successful organ transplantation. 5 studies reported no association with graft function, while 6 studies did. 5 studies reported on recipient survival, 3 of which suggested donor sodium is unlikely to be associated with recipient survival. The included studies had serious risk of bias, and the certainty in evidence was deemed to be very low. CONCLUSION: In low risk of bias studies, donor sodium dysregulation is unlikely to affect kidney graft function or mortality of heart and kidney recipients, but the certainty in the evidence is very low due to inconsistency and imprecision. Further research is required to refine the serum sodium target range, quantify the dose-response curve, and identify organs most vulnerable to sodium dysregulation.