Abstract
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).