Sitagliptin in type 2 diabetes mellitus: Efficacy after five years of therapy

The aim of this study was to investigate whether the positive effects of sitagliptin were maintained even after five years of treatment. Starting from 2008 to today, we treated 624 patients, not well controlled by current therapy, with the addition of sitagliptin 100 mg/die. Patients included 216 subjects treated with metformin, 206 treated with sulfonylureas, and 202 treated with pioglitazone. Sitagliptin was added to metformin, sulfonylureas and pioglitazone in monotherapy, respectively, and the data were compared with those of 620 patients treated with sulfonylureas+metformin, pioglitazone+metformin and pioglitazone+sulfonylureas matched for age, sex, diabetes duration. We recorded that the addition of sitagliptin to current hypoglycemic therapy led to a reduction of HbA1c similar to that obtained with sulfonylureas after two years. After five years of treatment, changes in HbA1c suggest a better glycemic control over the long term with sitagliptin compared to other treatments, particularly when compared with sulfonylureas. The other parameters evaluated as fasting plasma glucose, post-prandial plasma glucose and insulin levels, confirm the trends observed for the value of HbA1c. Regarding BMI, it increased with sulfonylureas and pioglitazone compared to sitagliptin. Patients treated with sulfonylureas had a higher incidence of hypoglycemia compared to sitagliptin. In conclusion, sitagliptin seems to maintain its positive effects on glycemia and fasting plasma insulin on the long term.