Serum Magnesium Levels in Chronic Kidney Disease with and without Diabetes Mellitus and its Correlation with Calcium and Phosphate Levels: A Case-control Study

Introduction: Nearly 10% of the world population is affected by Chronic Kidney Disease (CKD). Hypermagnesaemia is seen in late stages of CKD whereas Diabetes Mellitus (DM) is commonly associated with hypomagnesaemia. Monitoring Mg levels and early correction may prevent the future risk for cardiovascular and CKD.

Aim: To compare the serum Mg levels in healthy controls, diabetic patients without CKD, late stages of CKD with and without diabetes and to evaluate its correlation with serum phosphate and calcium levels in CKD patients.

Materials and Methods: A case-control study was conducted in Vydehi Institute of Health Sciences and Research Centre, Bangalore, Karnataka, India from January 2018 to December 2019. A total of 100 participants were divided into four groups of 25 each. Group I were healthy controls, Group II were DM patients without CKD, Group III CKD stage 3 and more without DM and Group IV CKD stage 3 and more with DM. Serum creatinine, urea, estimated Glomerular Filtration Rate (eGFR), calcium, phosphorous and magnesium levels were estimated in all the groups. Analysis of Variance (ANOVA) and Pearson’s correlation was used to statistically analyse the data.

Results: The Group III participants who had CKD but no DM were relatively younger in age (mean age 48.5±5.5 years) compared to other groups and there was a significant difference in the age group between four groups (p-value 0.0113). Though there was a male preponderance in all the four groups, the gender difference was not significant. Significant difference in the Mg was observed between the four groups (p-value <0.001). The DM group showed low serum magnesium. CKD patients with and without DM showed high but within reference range Mg levels. Sub-group analysis revealed DM patients on haemodialysis had lower Mg level as compared to non DM. Mg levels in CKD showed significant positive correlation with phosphorous levels (r-value 0.5002, p-value 0.0002).

Conclusion: High levels of Mg in late stages of CKD are expected but CKD with DM had relatively low Mg level. Low Mg level was also seen in DM patients on haemodialysis.