Fractional excretion of magnesium as an early indicator of renal tubular damage in normotensive diabetic nephropathy

Abstract

Abstract Objectives The aim of the present study is to evaluate the diagnostic powers of fractional magnesium, sodium and potassium as markers of renal tubular damage in normotensive type 2 diabetes mellitus (T2DM) patients with respect to microalbuminuria and estimated glomerular filtration rate (eGFR). Materials and methods Forty healthy volunteers and 91 normotensive T2DM patients were included in the study. Patient group was divided into two according to albuminuria level; 49 were normoalbuminuric and 42 were microalbuminuric. In addition to albumin in urine, urine and serum Na, K, Mg and creatinine values were measured to calculate fractional electrolyte excretion rates. Results In normoalbuminuric and microalbuminuric groups, fractional excretion of magnesium (FEMg) values were found to be significantly higher than the control group (p < 0.05). There was a moderate correlation between FEMg and albümin to cratinin ratio (ACR) (Spearman r = 0.3215, p < 0.05). In the ROC analysis for eGFR and FEMg based on microalbuminuria, the areas under the curve were 0.625 and 0.732, respectively (diagnostic sensitivity 59.52% and 66.67%; specificity 70.79% and 77.53%, p < 0.05). Conclusion For renal tubular damage predicted by microalbuminuria, FEMg could be accepted as a candidate biochemical marker with diagnostic and prognostic value.