Combination therapy of sitagliptin and metformin is an effective and safe treatment for type 2 diabetes

This study investigated the effectiveness and safety of a combination therapy of sitagliptin (Januvia) and metformin (Glucophage) for type 2 diabetes patients.

Type 2 diabetes (T2D) is characterized by elevated blood glucose (sugar) levels. The main aim of treatment is to reduce blood glucose levels. This can be monitored by measuring HbA1c levels (average blood glucose over 3 months). Metformin is typically the first treatment of T2D. Usually, additional drugs such as sitagliptin are eventually required to control blood glucose levels. Combination therapy with sitagliptin and metformin is a common treatment choice. Studies have demonstrated that this combination therapy leads to an average HbA1c reduction of 0.8% or greater.  However, the long-term effectiveness and safety of sitagliptin and metformin combination therapy needs to be determined.

This study investigated the effectiveness and safety of combination therapy of sitagliptin and metformin for type 2 diabetes patients, over a period of 4 years. Of 890 patients who started the study, 357 patients completed the full 4 years. All patients were treated with sitagliptin and metformin for 4 years. HbA1c was measured at the beginning of the study and every 3-6 months thereafter. Patients were classed as responsive to treatment if they achieved a reduction in HbA1c of 0.8% or more, or if they achieved an HbA1c of 7.0% or less.

88.2%of patients who completed the study were responsive to treatment. Responders had an average decrease of 1.57% in HbA1c levels during the first 3 months of treatment. This was followed by a further 0.53% decrease over the next 3 months. HbA1c levels then remained relatively constant until the end of the study. In contrast, the average reduction in HbA1c level in the nonresponders in the first 3 months was 0.6%. HbA1c levels in the nonresponders then varied between 7.5% and 8.0% for the rest of study.

Patients with a high HbA1c level at the beginning of the study were more likely to respond to treatment. There were no reports of any serious side effects to treatment. 

The authors concluded that a combination therapy of sitagliptin and metformin safely and effectively reduced HbA1c in the long-term in type 2 diabetes patients.

Some patients were treated with other drugs as required. This may have affected the results.

Consult your doctor if you would like to discuss beginning sitagliptin and metformin combination therapy.