Two injections or more? Comparing the effectiveness of insulin degludec and aspart combinations

This study compared the safety and effectiveness of separate insulin degludec and insulin aspart injections versus the two insulins combined in one injection.

There are many types of insulin available for patients with type 2 diabetes (T2D). Insulin ranges from rapid-acting to ultra-long acting. Rapid-acting insulin, such as insulin aspart (Novorapid) is injected after meals and lasts for 4 hours. Insulin degludec (Tresiba) is an ultra-long acting insulin injected once daily. It reduces blood glucose levels over 40 hours.

Some T2D patients may only require longer-acting insulin. However, injecting rapid-acting insulin at mealtime may prevent the rise in blood glucose levels which occurs after eating. This requires patients to inject insulin many times throughout the day. Patients may not comply with multiple daily injections. Patients may be more likely to comply with a premixed formula of insulin aspart and insulin degludec (both insulins present in one injection) twice daily. Improve treatment compliance could improve the HbA1c (average blood glucose levels over three months).

This study aimed to determine the safety and effectiveness of insulin aspart and insulin degludec injected twice daily.

This study included 274 T2D patients. 138 participants injected the combination of insulin aspart and insulin degludec (IDegAsp) twice daily with main meals. 136 participants injected insulin degludec once daily and insulin aspart 2-4 times daily (IDeg+Asp). Patients were followed for 26 weeks.

After 26 weeks, participants who received IDegAsp had an average HbA1c of 7%. Participants who received IDeg+Asp had an average HbA1c of 6.8%. IDegAsp was not shown to have a greater improvement in the HbA1c compared to IDeg+Asp.

Participants treated with IDegAsp required less insulin. This group of patients also had a smaller reduction in body weight. Hypoglycaemia (dangerously low blood glucose levels) occurred less often in participants treated with IDegAsp. In addition, patient satisfaction with regard to social functioning was higher in the IDegAsp group.

This study concluded that both IDegAsp and IDeg+Asp improve control of blood glucose levels. Although IDegAsp is not superior to IDeg+Asp, patients treated with IDegAsp had greater satisfaction.

Additional factors such as race, diet and lifestyle were not accounted for during the study.