BackgroundSitagliptin is a DPP-4 inhibitor that became available for use in Japan three years ago. This study was conducted to identify the pleiotropic effects of sitagliptin other than blood glucose lowering in Japanese type 2 diabetes mellitus patients.MethodsA retrospective, observational study of 940 type 2 diabetes mellitus patients was conducted. The primary outcome measures were HbA1c, blood pressure, and lipid profiles measured at 0, 4, and 12 weeks of sitagliptin therapy.ResultsAfter 12 weeks of sitagliptin treatment, compared with baseline, HbA1c decreased 0.64% ± 0.86%; systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased significantly; and serum creatinine (Cr) and uric acid (UA) levels were mildly but significantly elevated. A correlation analysis of the changes in systolic blood pressure, diastolic blood pressure, creatinine, and uric acid (ΔSBP, ΔDBP, ΔCr, ΔUA) from baseline to 12 weeks showed significant negative correlations between ΔSBP and ΔCr, ΔSBP and ΔUA, and ΔDBP and ΔCr. Total cholesterol and postprandial triglycerides were significantly decreased at both 4 and 12 weeks. Alkaline phosphatase (ALP) decreased significantly, and there was a significant positive correlation between changes in ALP and HbA1c.ConclusionsSitagliptin seems to be effective not only in lowering blood glucose but also in lowering blood pressure, lipid, and ALP levels. Sitagliptin appears to contribute to a Na-diuretic action due to GLP-1.

BackgroundThere have only been a few reports about use of dipeptidyl peptidase 4 (DPP-4) inhibitors in elderly patients with type 2 diabetes mellitus (T2DM), suggesting that the safety of these agents has not been sufficiently demonstrated. We performed a comparative review of the efficacy and safety of sitagliptin for Japanese patients with T2DM managed in the real-world clinical setting.MethodsAn age-stratified analysis was performed of 831 patients who were treated with sitagliptin for 2 years. Parameters assessed included the hemoglobin A1c (HbA1c), body weight, serum creatinine, and adverse events. HbA1c and the incidence of hypoglycemia were also evaluated in patients treated with sitagliptin and a sulfonylurea (SU), who were divided into three age groups (<65 years, 65–74 years, and ≥75 years).ResultsComparison of glycemic control parameters, laboratory values, and adverse events revealed significant improvement of HbA1c, casual postprandial plasma glucose, and fasting plasma glucose in each age group with no change in body weight. Serum creatinine increased significantly in all age groups. Hypoglycemia only occurred in patients who received combined treatment with an SU and sitagliptin, and there was no age-related difference in its incidence.ConclusionsHbA1c was improved by 2 years of sitagliptin therapy in all three age groups, and age did not seem to influence the incidence of hypoglycemic events. These results confirm the efficacy and safety of sitagliptin in patients ≥ 75 years old, suggesting that it is also useful for treating elderly patients with T2DM.

(J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00221.x, 2012) Aims/Introduction:  To determine the efficacy and safety of sitagliptin monotherapy and combination therapy in Japanese type 2 diabetes patients after 3 months’ therapy.Materials and Methods:  A retrospective, observational study of 741 type 2 diabetes patients was carried out; 110 received sitagliptin monotherapy, and 631 received combination therapy with sitagliptin when other oral medications were insufficient. The primary outcome measure was glycated hemoglobin (HbA1c) measured at 0, 4 and 12 weeks of sitagliptin therapy.Results:  In the monotherapy and combination therapy groups, HbA1c decreased significantly after 12 weeks. Target HbA1c (<7%) was achieved in 39.1% overall. On logistic regression analysis, baseline HbA1c was the strongest contributing factor for achieving target HbA1c; baseline body mass index and duration of diabetes were also significant factors. A total of 82 patients (11%) were unresponsive to sitagliptin. These patients’ baseline body mass index was significantly higher and their baseline HbA1c was significantly lower than those of patients who responded to sitagliptin. The most commonly co‐administered drugs were sulfonylureas (508 patients). In these patients, the dose of sulfonylurea decreased with time. In 66 patients whose sulfonylurea dosage was reduced when sitagliptin was started, HbA1c and bodyweight decreased significantly after 12 weeks. A total of 24 patients receiving sulfonylureas had mild hypoglycemia, but none discontinued sitagliptin.Conclusions:  Sitagliptin was effective and safe as both monotherapy and combination therapy in Japanese type 2 diabetes patients. When sulfonylureas were ineffective, sitagliptin improved glycemic control. In patients whose sulfonylurea dose was reduced at the start of sitagliptin, blood glucose improved and bodyweight decreased after 12 weeks.

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Aims/Introduction:  The prevalence of diabetes mellitus is increasing rapidly in Japan, and diabetic neuropathy is a major factor decreasing diabetic patients’ quality of life, as well as a risk factor for sudden death. The present study aimed to determine the prevalence of diabetic neuropathy and raise awareness about it among patients and their physicians.Materials and Methods:  Diabetic outpatients (N = 5077) at 249 medical institutions within Kanagawa Prefecture, Japan, were surveyed by questionnaire and underwent foot examinations. The questionnaire included 10 questions about sensory abnormalities of both feet, muscle cramps and autonomic symptoms. Foot examinations included testing for vibratory perception of the medial malleolus, Achilles tendon reflexes and touch sensation of the bottom of the great toe using tissue paper.Results:  Of the 5077 patients surveyed, 70.4% reported symptoms. Overall, 75.4% of the patients underwent vibratory perception testing, of whom 44.9% had abnormal thresholds (≤10 s). On the tissue paper touch test, performed in 94.6% of patients, 11.9% had no touch sensation. Of the 2803 type 2 diabetic patients with known background factors who underwent foot examinations, 49.4% had diabetic neuropathy. There was a high prevalence of diabetic neuropathy (36.1%) in patients with <5‐year history. Of the patients with no touch sensation on the tissue paper test, 81.3% had diabetic neuropathy.Conclusions:  The present study identified the prevalence of diabetic neuropathy in Kanagawa Prefecture. The tissue paper test is a simple and excellent method of evaluating decreased superficial sensation that can help evaluate the severity of diabetic neuropathy. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00174.x, 2011)