Sitagliptin improves albuminuria in patients with type 2 diabetes mellitus

INTRODUCTION The aim of the present study was to determine the effect of sitagliptin on microalbuminuria in patients with type 2 diabetes mellitus. MATERIALS AND METHODS A total of 85 patients with type 2 diabetes mellitus (age >20 years, <80 years, hemoglobin A1c [HbA1c] <8.4%) were randomized to patients taking sitagliptin 50 mg or other oral glucose-lowering agents. The following parameters were evaluated at 0, 3 and 6 months after the treatment: bodyweight, blood pressure, HbA1c, fasting plasma glucose, fasting plasma insulin, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, estimated glomerular filtration rate and urinary albumin excretion. The primary outcome was changes in urinary albumin excretion at 6 months. RESULTS Significant and comparable falls in HbA1c and fasting plasma glucose were found in both groups. However, sitagliptin significantly reduced urinary albumin excretion within 6 months, especially in patients with high urinary albumin at baseline. A total of 27 patients with normoalbuminuria showed a reduction in urinary albumin excretion, suggesting that sitagliptin prevents the development of albuminuria. A total of 15 patients with albuminuria showed a reduction in urinary albumin excretion, suggesting the beneficial effect of sitagliptin in the early stage of diabetic nephropathy. There was a significant correlation between improvement of proteinuria and that of diastolic blood pressure. CONCLUSIONS The results suggested that sitagliptin improved albuminuria, in addition to improving glucose. The mechanism of the reduction of albuminuria by sitagliptin could be a direct effect, as well as an increase in active glucagon-like peptide-1, independently affecting blood pressure, bodyweight and glucose metabolism. This trial was registered with the University Hospital Medical Information Network (UMIN no. #000010871).