Lack of Influence of Serum Magnesium Levels on Overall Mortality and Cardiovascular Outcomes in Patients with Advanced Chronic Kidney Disease

Abstract

Background. Low serum magnesium has been associated with an increased cardiovascular risk in the general population and in dialysis patients. Our aim was to analyze the influence of serum magnesium on overall mortality and cardiovascular outcomes in patients with advanced CKD not yet on dialysis. Methods. Seventy patients with CKD stages 4 and 5 were included. After a single measurement of s-magnesium, patients were followed a mean of 11 months. Primary end-point was death of any cause, and secondary end-point was the occurrence of fatal or nonfatal CV events. Results. Basal s-magnesium was within normal range (2.1 ± 0.3 mg/dL), was lower in men (P = 0.008) and in diabetic patients (P = 0.02), and was not different (P = 0.2) between patients with and without cardiopathy. Magnesium did not correlate with PTH, calcium, phosphate, albumin, inflammatory parameters (CRP), and cardiac (NT-proBNP) biomarkers but correlated inversely (r = −0.23; P = 0.052) with the daily dose of loop diuretics. In univariate and multivariate Cox proportional hazard models, magnesium was not an independent predictor for overall mortality or CV events. Conclusions. Our results do not support that serum magnesium can be an independent predictor for overall mortality or future cardiovascular events among patients with advanced CKD not yet on dialysis.

Serum Magnesium and Mortality in Maintenance Hemodialysis Patients

“…It is uncertain whether lower serum magnesium is the cause of malnutrition or the consequences of it. Although some studies have suggested that a lower serum magnesium level was a significant and independent predictor of CV mortality among chronic hemodialysis patients, the results have been inconsistent [13,14] . We believe that lower serum magnesium may be the only manifestation of malnutrition, which is not the initiating factor and may not play an independent role in atherosclerosis.…”

Magnesium: A Magic Bullet for Cardiovascular Disease in Chronic Kidney Disease?

“…However, a study in 283 patients with CKD (eGFR 30–59, 15–29, and <15 (not on dialysis)) in, respectively, 101, 86, and 96 patients), that were included from the moment of first referral to a Turkish renal unit because of renal failure, did show a statistically significant inverse relation between serum magnesium and cardiovascular fatal and nonfatal events (adjusted HR 0.21 (0.10–0.46) per 0.411 mmol/L higher serum Mg) [ 36 ]. Another study did not find a statistically significant relation between serum magnesium concentration and all-cause mortality [ 37 ]. In this study, follow-up ended after occurrence of a nonfatal cardiovascular event and this approach may, thus, have missed subsequent events, including cardiovascular mortality and all-cause mortality, leading to bias in the analysis of all-cause mortality [ 37 ].…”

“…Another study did not find a statistically significant relation between serum magnesium concentration and all-cause mortality [ 37 ]. In this study, follow-up ended after occurrence of a nonfatal cardiovascular event and this approach may, thus, have missed subsequent events, including cardiovascular mortality and all-cause mortality, leading to bias in the analysis of all-cause mortality [ 37 ]. Collectively, the epidemiological studies demonstrate an association between a low serum magnesium concentration and both all-cause and cardiovascular mortality.…”

Serum Magnesium Levels and Mortality in Japanese Maintenance Hemodialysis Patients

“…Although some studies have suggested that lower serum Mg is a significant and independent predictor of CVD mortality among chronic HD patients, the results have been inconsistent [19,20]. We think that lower serum Mg may be a manifestation of malnutrition, which is not the initiating factor and may not play an independent role in atherosclerosis.…”