Evaluation of the Urinary Kidney Injury Molecule-1 Levels in Patients With Diabetic Nephropathy

Purpose: Kidney Injury Molecule-1 is a protein that increases in urine following tubular damage. Kidney Injury Molecule-1 levels were correlated with the level of chronic kidney disease secondary to diabetic nephropathy in patients with type 2 Diabetes Mellitus. Methods: Clinical and laboratory findings of 142 patients with diabetic nephropathy and 34 control subjects were analysed. Creatinine and HbA1c levels in blood samples and albumin, creatinine and Kidney Injury Molecule-1 levels in urine samples were assessed. Results: Urinary Kidney Injury Molecule-1 levels were significantly increased both in subgroups of diabetic nephropathy (normo-/micro-/macro-albuminuria) and in chronic kidney disease (stage 2-4) compared with controls. Urinary Kidney Injury Molecule-1 levels in stage 2 chronic kidney disease patients were significantly higher than those of the patients with stage 3-4 chronic kidney disease. Urinary Kidney Injury Molecule-1 levels, along with urinary albumin excretion and the duration of diabetes, were found to be independent risk factors associated with low glomerular filtration rates. Conclusion: Urinary Kidney Injury Molecule-1 levels seems to predict renal injury secondary to diabetic nephropathy in early period independent of albuminuria, because urinary Kidney Injury Molecule-1 was elevated despite normal urinary albumin excretion in the normoalbuminuric subgroup. Urinary Kidney Injury Molecule-1 levels, which are elevated in primarily in stage 2, shows a gradual decrease in patients with chronic kidney disease stages 3 and 4; thus, urinary Kidney Injury Molecule-1 levels may be useful in tracking the progression of kidney disease.