Serum Magnesium and Progression of Coronary Artery Calcification: A Report from the Chronic Renal Insufficiency Cohort (CRIC) Study.

BACKGROUND

Magnesium may play a protective role against the progression of vascular calcification in CKD, however the evidence remains scarce. This study aims to evaluate the association between serum magnesium level and progression of coronary artery calcification (CAC) in individuals with CKD.

METHODS

A total of 2017 CRIC participants with serum magnesium and CAC scans were included in the study. Baseline magnesium level was analysed both as continuous and a categorized variable by tertiles: low (1.7±0.17mg/dl), mid (2.0±0.05mg/dl), and high (2.2±0.14mg/dl). The cohort of participants with at least two CAC scans (N=1044) was used to assess CAC progression, defined as: CAC baseline=0 & CAC follow-up >0, OR annualized change in CAC ((CAC follow-up-CAC baseline)/ year) ≥50 Agatston units among participants with prevalent CAC at baseline. Logistic regression models were built to study the association of interest.

RESULTS

The mean age was 56±11 years and 46% were women. The mean Agatston score was 342±762. In models with increasing adjustment for demographic, clinical, and mineral metabolism variables, each unit increase in baseline serum magnesium was associated with 43% lower odds of CAC >400 (OR 0.57, 95% CI [0.35-0.93], p = 0.03. However, serum magnesium level was not significantly associated with CAC progression (OR 0.73, 95% CI [0.36-1.51]. In sensitivity analyses stratified by median serum phosphorus level, evidence of effect modification was not consistent across the two different definitions of CAC progression.

CONCLUSIONS

In a large cohort of patients with CKD stage 2-4, higher serum magnesium level was associated with lower odds of severe CAC at baseline, but not with CAC progression over time. These findings suggest a potential protective association between magnesium and prevalent vascular calcification, although confirmation in larger longitudinal and interventional studies is needed.