Type 2 Diabetes – How do different therapy combinations affect cardiovascular health?

This study investigated the effect of 3 different therapy combinations on the occurrence of cardiovascular disease in type 2 diabetes.

There are a number of types of drugs that can be used to treat diabetes. Metformin (Glucophage) decreases glucose production, and is often the first choice of treatment for type 2 diabetes. Commonly, other drugs are prescribed to be taken alongside metformin. Dipeptidyl peptidase-4 (DPP-4) inhibitors (Januvia, Tradjenta, Galvus) increase insulin release from the pancreas and reduce blood glucose (sugar) levels. Sulfonylureas (Amaryl, Glucotrol, DiaBeta) increase the amount of insulin produced by the pancreas. Pioglitazone (Actos) increases insulin sensitivity (how well the body reacts to insulin). 

Diabetes patients in general have a higher risk of cardiovascular complications, and so it is important to determine whether any type of diabetes treatment adds to this risk. 

This study aimed to compare the association of the following drug combinations with cardiovascular disease risk: metformin and DPP-4 inhibitors, metformin and sulfonylureas and metformin and pioglitazone.

There were 349,427 study participants who were followed for an average of 2.1 years. 74,270 were treated with metformin and a DPP-4 inhibitor. 253,563 were treated with metformin and a sulfonylurea. 21,193 participants were treated with metformin and pioglitazone.

Compared to participants treated with metformin and a DPP- 4 inhibitor, participants treated with metformin and a sulfonylurea had a 20% increased cardiovascular risk. Participants treated with metformin and pioglitazone had an 11% reduced cardiovascular risk. However there was a higher risk of heart failure in participants treated with metformin and pioglitazone compared to those treated with metformin and a DPP- 4 inhibitor. 

The authors of this study suggested that  a DPP – 4 inhbitor should be the first additional drug combined with metformin in type 2 diabetes. The combination of metformin and pioglitazone  was also presented as a viable treatment option, but only in those who have a low risk of heart failure. 

There were a number of limitations to this study. Firstly, the number of participants in each study group was not consistent. Management of participants’ glucose levels was not taken into account. Finally, the study participants were chosen from a national health insurance claims database. Hence, the group of study participants may not accurately reflect the whole community of T2D patients.