Clinical implications of changes in metabolic syndrome status after kidney transplantation: a nationwide prospective cohort study.

BACKGROUND: Metabolic syndrome (MetS) is prevalent in patients with end-stage kidney disease, and kidney transplantation is expected to modify the metabolic status. However, whether changes in metabolic status at the time of transplantation affect recipient outcomes remains unclear. METHODS: We analyzed 4187 recipients registered in a nationwide prospective cohort from 2014 to 2020. MetS was defined as the presence of three or more components of the metabolic syndrome. Patients were classified based on the pre- and post-transplant MetS status: MetS-free, MetS-developed, MetS-recovered and MetS-persistent. Study outcomes were occurrence of death-censored graft loss and a composite of cardiovascular events and death. RESULTS: Among recipients without pre-transplant MetS, 19.6% (419/2135) developed post-transplant MetS, and MetS disappeared in 38.7% (794/2052) of the recipients with pre-transplant MetS. Among the four groups, the MetS-developed group showed the worst graft survival rate, and the MetS-persistent group had a poorer composite event-free survival rate. Compared with the MetS-free group, the MetS-developed group was associated with an increased risk of graft loss [adjusted hazard ratio (aHR) 2.35; 95% confidence interval (CI) 1.17-4.98] and the risk of graft loss increased with increasing numbers of dysfunctional MetS components. MetS-persistent was associated with increased risks of cardiovascular events and death (aHR 2.46; 95% CI 1.12-5.63), but changes in the number of dysfunctional MetS components was not. CONCLUSION: Kidney transplantation significantly alters the metabolic status. Newly developed MetS after transplantation was associated with an increased risk of graft loss, whereas persistent MetS exposure before and after transplantation was associated with increased risks cardiovascular events and patient survival.