Association of serum magnesium with all-cause mortality in patients with and without chronic kidney disease in the Dallas Heart Study

Nephrology Dialysis Transplantation
Q1
Aug 2018
Citations:38
Influential Citations:4
Observational Studies (Human)
80
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Enhanced Details

Methods
Population: multiethnic adults aged 30–65 years from the Dallas Heart Study; observational, population-based cohort; 3,551 participants with baseline fasting serum magnesium measured; CKD defined as eGFR <60 mL/min/1.73 m2 and/or albumin/creatinine ratio above sex-specific thresholds (17 mg/g in men, 25 mg/g in women; sensitivity analysis used KDIGO criteria); data from DHS-1 (2000–2002) and DHS-2 (2007–2009); follow-up for mortality and cardiovascular events; statistical approach: multivariable Cox proportional hazards models.
Results
Low serum magnesium (SMg) levels independently associated with higher all-cause mortality, especially in CKD. Each 0.2 mg/dL decrease in SMg increased the hazard of all-cause death by 31% in the overall cohort (HR 1.31; 95% CI 1.14–1.49); 37% in CKD (HR 1.37; 95% CI 1.08–1.75) and 22% in non-CKD (HR 1.22; 95% CI 1.04–1.45). In CKD, the lowest SMg tertile conferred higher risk of all-cause death vs highest tertile (HR 2.31; 95% CI 1.23–4.36). The association with CV death or events was not statistically significant. Cross-sectional analyses showed inverse associations of SMg with systolic/diastolic blood pressure and with insulin resistance (HOMA-IR). Low SMg (1.4–1.9 mg/dL; 0.58–0.78 mM) independently linked to higher all-cause mortality in CKD; randomized trials are needed to determine whether Mg supplementation improves survival in CKD.
Limitations
Small number of adjudicated all-cause and cardiovascular deaths/events in the full cohort; limited power in CKD subgroup for cardiovascular surrogate markers; potential residual confounding; SMg measured with two different laboratories across DHS phases; absence of time-varying SMg assessment; CKD definitions used varied (eGFR/ACR thresholds).

Abstract

Background Low serum magnesium (SMg) has been linked to increased mortality and cardiovascular disease (CVD) in the general population. We examined whether this association is similar in participants with versus without prevalent chronic kidney disea...