Spain: Magnesium supplementation to patients with chronic kidney disease (CKD) should be considered with caution, suggests results from a recent study in the Journal of Renal Nutrition. According to the study, high levels of magnesium increases risk of death and cardiovascular (CV) events in CKD patients.
In the general population, hypermagnesemia is associated with overall mortality and hypomagnesemia with cardiovascular events. However, in CKD patients the evidence is not so strong. Isabel Galán, Avenida Intendente Jorge Palacios, Murcia, Spain, and colleagues aimed to investigate the relationship between serum magnesium (SMg) concentration and cardiovascular morbidity and mortality, all-cause mortality, and the progression to kidney failure in a CKD patients.
For the purpose, the researchers performed an observational study of a cohort of 746 CKD patients (aged 70 ± 13 years) -- 62.9% were male, 45.2% had CKD grade 3, and 35.9% grade 4. The researchers collected baseline characteristics and analytical profile of the patients at the first visit and they were followed for a mean of 42.6 months.
Key findings of the study include:
The mean SMg concentration was 2.09 ± 0.33 mg/dL, with a close correlation between SMg concentration and serum creatinine, phosphorus, and intact parathyroid hormone (iPTH) values.
Use of calcitriol was associated with higher SMg (SMgH) concentration, while calcium supplements and proton pump inhibitors (PPIs) were associated with lower SMg concentration.
For risk of cardiovascular events, patients with hypermagnesemia had an overall higher risk on a crude analysis (Log Rank 4.83) and adjusted analysis (HR = 1.34).
For risk of all-cause mortality, patients with hypermagnesemia had an overall higher risk on crude analysis (Log Rank 13.11) and adjusted analysis (HR = 1.5424).
After performing a propensity score matching for SMg concentration, the researchers achieved two comparable groups of 287 patients, finding again higher all-cause mortality in the hypermagnesemia group (LogRank 15.147), that persisted in the Cox model adjusted for calcium, phosphorus, and iPTH.
No association was found between SMg concentration and initiation of kidney replacement therapy (KRT).
"Magnesium concentration increases with decreasing kidney function. Hypermagnesemia predicts cardiovascular events and all-cause mortality in this same population. Thus, magnesium supplementation should be used with caution in these patients," wrote the authors.
The study titled, "Impact of Serum Magnesium Levels on Kidney and Cardiovascular Prognosis and Mortality in CKD Patients," is published in the Journal of Renal Nutrition.
DOI: https://www.sciencedirect.com/science/article/abs/pii/S1051227620302661