Effects of Magnesium Supplementation on Clinical and Biochemical Outcomes in Patients with Chronic Kidney Disease: A Systematic Review of Randomized Controlled Trials

Chronic kidney disease (CKD) is associated with metabolic and cardiovascular complications, as well as mineral and bone disorders. Hypomagnesemia occurs in some patients with CKD and has been associated with disease progression and increased mortality. Magnesium supplementation may improve various clinical and biochemical outcomes; however, findings across studies remain inconsistent. A systematic literature search was conducted using electronic databases, including PubMed and Embase, to identify randomized controlled trials (RCTs) evaluating oral magnesium supplementation in adults with CKD. The outcomes assessed included vascular parameters, kidney function, metabolic outcomes, mineral and bone metabolism parameters, inflammatory markers, and safety. Ten RCTs met the eligibility criteria, including seven studies involving patients with nondialysis-dependent CKD and three involving patients undergoing hemodialysis. Intervention durations ranged from 8 weeks to 2 years. Magnesium supplementation demonstrated potential benefits for certain vascular outcomes, particularly carotid intima-media thickness (cIMT) and serum calcification propensity, as measured by the T50 test, as well as selected metabolic parameters. However, its effects on coronary artery calcification (CAC) progression, kidney function, mineral and bone metabolism, inflammation, and oxidative stress were inconsistent across studies. No cases of severe symptomatic hypermagnesemia were reported, although gastrointestinal adverse effects, particularly diarrhea, were among the most frequently reported adverse events. Oral magnesium supplementation may provide benefits for selected vascular and metabolic outcomes in patients with CKD. However, the available evidence remains inconsistent and insufficient to support routine magnesium supplementation in all patients with CKD.