The link between lower serum magnesium and kidney function in patients with diabetes mellitus Type 2 deserves a closer look

Introduction: We previously reported that lower serum magnesium levels [Mg²⁺] can be associated with more rapid decline in renal function in patients with diabetes mellitus Type 2 (DM2). We now report long-term renal outcomes of the same patient cohort. Materials and methods: Most recent serum creatinine (SCr) and routine urinary analyses (RUA) for the 550 DM2 patients from our original study were collected. Data analysis: Patients with follow-up data were stratified according to the original study: Group 1 had initial [Mg²⁺] ≤ 1.6 mg/ dl, Group 2 > 1.6 - 1.8 mg/dl, Group 3 > 1.8 - 2.0 mg/dl and Group 4 > 2.0 mg/dl. The change in renal function was defined by the ratio of the most recent to the initial SCr as well as slope of 1/ SCr-versus-time. Any level of proteinuria detected from RUA provided evidence for overt proteinuria. Renal outcomes were analyzed for each defined patient group. Results: SCr were available for 329 out of 550 patients (59.8%). The duration of follow-up ranged from 93.8 ± 23.4 - 99.4 ± 22.4 months among 5 groups. The ratios of the most recent to the initial SCr were 1.54 ± 1.01, 1.28 ± 0.51, 1.26 ± 0.57 and 1.09 ± 0.29 for Groups 1 - 4, respectively; where the differences between Groups 1, 2 and 3 against Group 4 were significant (p = 0.02, 0.001 and 0.007, respectively). Accordingly, the mean slope of 1/SCr-versus-time was the best for Group 4. RUA were available for 176 patients: 22.2%, 9%, 7.3% and none from Groups 1 to 4, respectively, developed overt proteinuria. Conclusion: Our follow-up data suggest a link between low [Mg²⁺] and worse renal outcomes in DM2 patients.