Long acting insulin versus sitagliptin (Januvia) in type 2 diabetes not controlled with metformin (Glucophage) alone

This study compared the safety and efficacy of Insulin glargine (Lantus) versus Sitagliptin (Januvia) in the management of type 2 diabetes mellitus (T2DM) poorly controlled by Metformin (Glucophage) alone. Main findings: insulin glargine provides better glycemic control than Sitagliptin when added to Metformin therapy.

Metformin is the drug of choice for T2DM. Other drugs are added if Metformin is not enough to control blood sugar. Insulin glargine is a long-acting insulin given once a day. Sitagliptin belongs to a class of drugs called dipeptydil peptidase 4 (DPP-4) inhibitors. They work by blocking the release of glucagon (the hormone that raises blood sugar, thereby contradicts the action of insulin) and increasing insulin release by the pancreas.

Diabetes control is usually assessed according to glycated hemoglobin (HbA1c) levels. This reflects the average blood glucose levels over a period of the last 3 months.

The present study involved 515 patients assigned to two groups. One group (250 patients) received Insulin glargine while the other (265 patients) received Sitagliptin. Patients were between 35 and 70 years old and received this treatment in addition to Metformin for 24 weeks. The mean reduction in HbA1c was compared at the end of the study.

Insulin glargine lowered HbA1c by 1.72%, while sitagliptin only by 1.13%. The difference was significant and suggested a better efficacy of Insulin glargine. A small increase in body weight was found with Insulin glargine use (+0.4 kg), while a decrease was demonstrated with Sitagliptin (-1.1 kg). Symptomatic hypoglycemia (drop in blood sugar levels) was more frequent in the Insulin glargine group.

These results suggest that glycemic control is better with Insulin glargine compared to Sitagliptin when either is added to Metformin. However, insulin therapy requires careful self-management of diabetes, with frequent blood sugar checks. These are essential in order to prevent hypoglycemia, which can sometimes be life-threatening. Moreover, insulin administration may lead to weight gain. Therefore, Sitagliptin might be a more appropriate choice for older or sicker patients who might be unable to strictly monitor their diabetes, or to obese T2DM patients.

This study was funded by Sanofi-Aventis, the manufacturer of insulin glargine.