Serum Magnesium Is Inversely Associated With Heart Failure, Atrial Fibrillation, and Microvascular Complications in Type 2 Diabetes.

Objective: We investigated whether serum magnesium (Mg ²⁺ ) was prospectively associated with macro- or microvascular complications and mediated by glycemic control (hemoglobin A _1c [HbA _1c ]), in type 2 diabetes (T2D).
Research Design and Methods: We analyzed in 4,348 participants the association of serum Mg ²⁺ with macrovascular disease and mortality (acute myocardial infarction [AMI], coronary heart disease [CHD], heart failure [HF], cerebrovascular accident [CVA], and peripheral arterial disease [PAD]), atrial fibrillation (AF), and microvascular complications (chronic kidney disease [CKD], diabetic retinopathy, and diabetic foot) using Cox regression, adjusted for confounders. Mediation analysis was performed to assess whether HbA _1c mediated these associations.
Results: The average baseline serum Mg ²⁺ concentration was 0.80 ± 0.08 mmol/L. During 6.1 years of follow-up, serum Mg ²⁺ was inversely associated with major macrovascular, 0.87 (95% CI 0.76; 1.00); HF, 0.76 (95% CI 0.62; 0.93); and AF, 0.59 (95% CI 0.49; 0.72). Serum Mg ²⁺ was not associated with AMI, CHD, CVA, and PAD. During 5.1 years of follow-up, serum Mg ²⁺ was inversely associated with overall microvascular events, 0.85 (95% CI 0.78; 0.91); 0.89 (95% CI 0.82; 0.96) for CKD, 0.77 (95% CI 0.61; 0.98) for diabetic retinopathy, and 0.85 (95% CI 0.78; 0.92) for diabetic foot. HbA _1c mediated the associations of serum Mg ²⁺ with HF, overall microvascular events, diabetic retinopathy, and diabetic foot.
Conclusions: Serum Mg ²⁺ concentration is inversely associated with the risk to develop HF and AF and with the occurrence of CKD, diabetic retinopathy, and foot complications in T2D. Glycemic control partially mediated the association of serum Mg ²⁺ with HF and microvascular complications.
(© 2021 by the American Diabetes Association.)