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

Abstract

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. Most recent serum creatinine (SCr) and routine urinary analyses (RUA) for the 550 DM2 patients from our original study were collected. Patients with follow-up data were stratified according to the original study: Group 1 had initial [Mg2+] < or = 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. 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. Our follow-up data suggest a link between low [Mg2+] and worse renal outcomes in DM2 patients.