A randomized crossover study of the efficacy and safety of switching from insulin glargine to insulin degludec among patients with type 1 diabetes

Abstract

The purpose of this study was to assess the efficacy of insulin degludec compared with insulin glargine and to find a safer way of switching from insulin glargine to insulin degludec. By use of a crossover design we compared preprandial blood glucose levels for patients with type 1 diabetes when insulin glargine or insulin degludec was injected in combination with pre-meal rapid-acting insulin. Insulin degludec was given before dinner at the same dose as insulin glargine to patients receiving insulin glargine once per day. When insulin glargine was given twice per day, the dose of insulin degludec was reduced by 20 % of the total dose of insulin glargine. We could safely replace insulin glargine with insulin degludec by use of this procedure without occurrence of severe hypoglycemia. There was no difference in fasting plasma glucose levels between insulin glargine and insulin degludec, indicating the appropriateness of the insulin degludec dose. However, blood glucose levels before lunch were lower when insulin degludec was used. Furthermore, the frequency of mild hypoglycemia was slightly higher before lunch in the period of insulin degludec injections, although the difference was not statistically significant. Thus, in type 1 diabetes, insulin degludec more effectively reduces glucose levels before lunch than does insulin glargine, probably as a result of steady supply of basal insulin. The potential risk of hypoglycemia before lunch may be reduced by reducing the morning dose of bolus insulin. For patients prone to hypoglycemia, it may be prudent to start insulin degludec injections at a lower dose.