One long-acting insulin may be better at controlling glycemic variations.
Glycemic variability, or the day-to-day upper and lower limits of blood glucose levels, can include both hypoglycemic and hyperglycemic episodes. Thus, glycemic variability can be a useful indicator of glycemic control and the development of long term complications. Although tighter controls in glycemic variability are desired, controlling glucose fluctuations in type 1 diabetes patients remain a challenge. One way to tighten glycemic variability is through the control of fasting blood glucose with the use of basal insulin. The use of intensive insulin therapies in people with type 1 diabetes place these patients at an increased risk for hypoglycemia. Patients fearing hypoglycemia have a harder time achieving optimal blood glucose levels. This in turn can limit a patient’s quality of life.
One study compared the glycemic variations of basal insulins; degludec and glargine. The open labeled crossover study evaluated 20 Japanese patients with at least 1-year history of type 1 diabetes. Patients had to first participate in a 12-week pre-study consisting of basal insulin and insulin aspart injections. Basal-Bolus doses were titrated to optimal fasting and postprandial blood glucose levels. During randomization, 10 participants were placed in the degludec treatment group while 10 participants were placed in the glargine treatment group. The first arm of the study occurred over a 12-week period. While continuing with the use of insulin aspart, participants injected their respective basal insulin in the mornings before breakfast. Patients then ‘crossed over’, or switched to the other study insulin for another 12-week trial period. Three days of continuous glucose monitoring was recorded blindly during the last week of each treatment group for each 12-week period. To evaluate glycemic variability, data collected from continuous glucose monitoring was used to calculate mean amplitude of glycemic excursions (MAGE) and J-Index. It is important to note that there is no ‘gold standard’ for assessing glycemic variability. Participants also completed the Diabetes Therapy-Related Quality of Life to evaluate their satisfaction with each treatment.
By using a student t test, researchers found no statistical difference between the two basal insulins in regard to mean glucose value (p = 0.435), optimum glucose value (p = 0.434), total hypoglycemia (0.300), Nocturnal hypoglycemia (p = 0.325), MAGE (p = 0.355), J-Index (p = 0.444) or mean fasting interstitial glucose (p = 0.102). Researchers did find a statistical difference; glargine had a larger day-to-day variation of blood glucose (p < 0.037). It also revealed better treatment satisfaction with the use of degludec (p < 0.009). In conclusion, degludec’s long duration of action may be a contributing factor for less glycemic variability, better control in fasting blood glucose and can also help to reduce the incidence of patient’s experiencing hypoglycemia. This in turn increases a patient’s satisfaction with treatment and result in a better quality of life for people with type 1 diabetes.
This study did have some limitations. Through the randomization process, the two treatment groups did have a statistically significant difference in HbA1C (7.1 ± 0.9 in degludec-glargine vs. 7.7 ± 0.6 in glargine-degludec; p = 0.077). It is unclear whether this difference confounded the results. Therefore, in order to confirm these preliminary findings, future long-term prospective studies should include larger sample size and a closed label randomization to prevent potential treatment bias.
- Glycemic variability can be a useful indicator of glycemic control and the development of long term complications.
- This study suggests patients may have higher treatment satisfaction and quality of life with the use of degludec.
- This study suggests degludec, as a basal insulin, is associated with less day-to-day variation in blood glucose.
Iga R, Uchino H, Kanazawa K, et al. Glycemic Variability in Type 1 Diabetes Compared with Degludec and Glargine on the morning injection: An Open-label Randomized Controlled Trial. Diabetes Ther. 2017. Epub 2017/05/25. doi: 10.1007/s13300-017-0269-0.
Suh S, Kim JH. Glycemic Variability: How Do We measure It and Why Is It Important? Diabetes & Metabolism Journal. 2015;39(4):273-282. doi: 10.4093/dmj.2015.39.4.273.
Joanna Martinez-Mendez, PharmD Candidate 2018, Lake Erie College of Osteopathic Medicine School of Pharmacy: FL Campus