Hypomagnesemia

Key Findings

• Across 38 randomized trials (n=2709), magnesium supplementation reduced systolic blood pressure by 2.81 mm Hg and diastolic blood pressure by 2.05 mm Hg versus placebo.
• Participants with hypomagnesemia had larger blood pressure reductions, with systolic blood pressure falling by 5.97 mm Hg and diastolic blood pressure by 4.75 mm Hg.

Key Findings

• Postoperative atrial fibrillation occurred in 19.2% of controls versus 1.9% of patients given continuous magnesium infusion after off-pump CABG (P = .008).
• Patients needing additional antiarrhythmic pharmacotherapy were more common without magnesium infusion (15.4% vs 1.9%, P = .031), while cardioversion and ICU stay were not significantly different.

Key Findings

• In 478901 ICU treatment windows, magnesium supplementation near usual institutional cutoffs was not associated with lower tachyarrhythmia risk, with a risk difference of 0.1% (95% CI, -4.2 to 6.9).
• Supplementation also showed no significant association with hypotension (risk difference 1.2%; 95% CI, -0.9 to 17.7) or death (risk difference 1.4%; 95% CI, -0.6 to 5.3).

Key Findings

• Over 4 months, magnesium supplementation increased plasma magnesium by 0.056 mmol/L (95% CI, 0.028 to 0.085; P < .001) and reduced fasting plasma glucose by 0.497 mmol/L versus placebo (P = .003).
• No significant between-group improvements were seen for HbA1c, insulin resistance, glycated albumin, or inflammatory markers despite the fasting glucose benefit.

Key Findings

• Among 6147 outpatients with HFrEF, 17.6% had magnesium below 0.75 mmol/L and 10.7% had magnesium above 0.95 mmol/L at baseline.
• The primary composite outcome rate was highest with hypermagnesemia at 34.9 per 100 person-years versus 21.5 with hypomagnesemia and 20.9 with normal magnesium, while sudden death and ventricular tachyarrhythmia rates did not differ across groups.