Which insulin is better for reducing blood glucose levels before hypoglycemia occurs?

This study compared two insulin types – degludec (Tresiba) and glargine (Lantus) – to see which was better at reducing blood glucose levels before hypoglycemia (dangerously low blood glucose levels) occurred. The study found that degludec improved blood glucose levels for longer than glargine before patients experienced hypoglycemia.

Treatment for both type 1 and type 2 diabetes (T1D and T2D) often involves insulin. Insulin is a drug that lowers blood glucose (sugar) levels. HbA1c is a test that indicates the level of a patient’s blood glucose for the previous three months.

There are different types of insulin available and each may have different effects. For example, some have longer-lasting effects. However, some patients develop low blood sugar levels (hypoglycemia). Hypoglycemia can lead to other dangerous complications. It is not clear if certain types of insulin are better than others at lowering blood glucose levels but preventing hypoglycemia.

501 patients with T1D and 721 patients with T2D were split into two groups. The first group received degludec for 32 weeks followed by glargine for 32 weeks. The second group received the same drugs in the reverse order. HbA1c levels were measured and hypoglycemia was indicated when HbA1c levels were below 3.1 mmol/L.

Glargine caused hypoglycemia in more patients than degludec.  After a 1% drop in HbA1c levels, 18% of patients with T1D experienced hypoglycemia with degludec compared to 34% of patients with glargine. 45% of patients with T2D experienced hypoglycemia after degludec compared to 67% of patients after glargine treatment.

Patients were able to reduce HbA1c levels for longer with degludec before hypoglycemia occurred. Degludec caused a HbA1c reduction of 0.7% more than glargine in patients with T1D before patients developed hypoglycemia. Degludec caused a HbA1c reduction of 0.96% more than glargine in patients with T2D before hypoglycemia occurred.

The authors concluded that degludec allowed better improvements in blood glucose levels before hypoglycemia occurred for patients with T1D or T2D. They also concluded that fewer patients developed hypoglycemia with degludec treatment than glargine.

The manufacturer of insulin degludec, Novo Nordisk, funded this study. This study was limited by its retrospective analysis of previous clinical trial results and did not record patients’ diets.