Is dapagliflozin add-on a good treatment option for patients with type 2 diabetes on insulin?

In this study, the authors evaluated the effectiveness of adding dapagliflozin (Farxiga) to insulin therapy in patients with uncontrolled type 2 diabetes (T2D). The study showed that compared to increasing insulin doses, dapagliflozin improved glucose control while reducing weight and hypoglycemia (dangerously low blood glucose levels) risk.

Insulin is a hormone produced by the pancreas to deliver sugar (glucose) from the blood into the cells. In type 2 diabetes (T2D), insulin is not able to carry glucose into the cells, resulting in increased blood glucose levels. Lifestyle changes and medications are the first treatment options for these patients. However, when these fail, patients need insulin injections to control their blood glucose.

In patients on insulin therapy, when the blood glucose is still not controlled with this treatment, increasing insulin doses is needed. However, this increases the risk of weight gain and hypoglycemia. Another option is adding another drug to therapy.

Sodium-glucose co-transporter-2 (SGLT2) inhibitors such as dapagliflozin are a newer class of antidiabetic drugs able to control glucose levels. They eliminate the excess of glucose from the body through the kidney into the urine. They also seem to reduce body weight and blood pressure. Whether adding dapagliflozin to insulin therapy leads to better outcomes than increasing insulin doses in patients with uncontrolled T2D on insulin therapy is still unknown. 

This study included 184 patients with uncontrolled T2D on insulin therapy. Half of the patients continued treatment with increasing doses of insulin (group 1) and half received 10 mg dapagliflozin daily to their initial insulin dose (group 2). Patients were evaluated after 1 year of therapy. Blood glucose control was evaluated through the HbA1c levels (average blood glucose control over the past 2-3 months). 

After 12 months, both groups had significant reductions in HbA1c levels. However, patients in group 2 had a greater reduction in HbA1c levels (by 0.9%) compared to group 1 (by 0.4%). 

Patients in group 2 had significant reductions in blood pressure. No significant reduction in blood pressure was seen in group 1. Also, after 12 months, patients in group 2 lost an average of 1.4 kg of body weight. Weight increased in group 1 by an average of 0.6 kg. 

Kidney function remained the same in group 2 while it tended to worsen in group 1. Also, group 2 had fewer hypoglycemia episodes (18.5%) compared to group 1 (32.6%). Daily insulin dose increased by 21.6% in group 1 but decreased by 4.5% in group 2.

The authors showed that dapagliflozin improved the outcomes of patients with uncontrolled T2D on insulin therapy. 

The patients were not randomly assigned to each group. Also, in group 1, the insulin dose was increased at each physician’s discretion. It may not have reached the optimal dose in some patients.