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Kidney Week

Abstract: PO2546

Post-Kidney Transplant Serum Magnesium Exhibits a U-Shaped Association with Subsequent Mortality

Session Information

Category: Transplantation

  • 1902 Transplantation: Clinical

Authors

  • Panthofer, Annalise Marie, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Lyu, Beini, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Astor, Brad C., University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Singh, Tripti, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Aziz, Fahad, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Mandelbrot, Didier A., University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Parajuli, Sandesh, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Mohamed, Maha A., University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Djamali, Arjang, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
  • Garg, Neetika, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
Background

Hypomagnesemia is common in kidney transplant recipients (KTR), likely due, at least in part, to renal magnesium (Mg) wasting related to calcineurin-inhibitor (CNI) use. The association of serum Mg levels and KTR outcomes may provide insight into the optimal serum Mg levels in this population.

Methods

KTRs between 01/2000 and 12/2016 at a large US transplant center who were alive with a functioning graft at 6 months post-transplant were included. Mean of the outpatient serum Mg in the baseline period, i.e. 6 to 18 months post-transplant, was used. Cox proportional-hazards regression was used to analyze the association between Mg and all-cause mortality, cause-specific mortality, and risk of new-onset cardiovascular events post-transplant.

Results

2,131 KTRs met our inclusion criteria. Mean number of Mg measurements per patient in the baseline period was 2.76. A U-shaped association between the mean baseline Mg level and all-cause mortality was observed in both unadjusted analysis and after adjusting for baseline characteristics, including eGFR and CNI levels. A mean Mg of 1.5 - 1.8 mg/dL was associated with the lowest incidence of death (Figure). Compared with Mg of 1.5 - 1.8 mg/dL, Mg level ≤ 1.5 mg/dL was also associated with higher incidence of mortality due to infection and arrhythmia but not ischemic heart disease or heart failure.

Conclusion

The relationship between serum Mg levels and mortality in KTRs is U-shaped. Interestingly, the risk is lowest with Mg levels 1.5 - 1.8 mg/dL; which represents the lower end of normal (1.6 - 2.6 mg/dL). Mg supplements for levels ≤ 1.5 mg/dL may be beneficial, but may cause increased renal wasting and diarrhea. Further studies are needed to understand why Mg > 1.8 mg/dL but well within the normal range was associated with higher risk despite adjustment for eGFR.

Funding

  • Private Foundation Support