Randomized crossover study to examine the necessity of an injection-to-meal interval in patients with type 2 diabetes and human insulin.

Abstract

Patients with diabetes and insulin therapy with human insulin were usually instructed to use an interval of 20-30 min between the injection and meal. We examined the necessity of the injection-to-meal interval (IMI) in patients with type 2 diabetes mellitus (T2DM) and flexible insulin therapy with human insulin. In this randomized, open crossover trial, 100 patients with T2DM (47% men, mean age = 66.7 years) were randomized to the IMI first group (phase 1, IMI 20 min; phase 2, no IMI) or IMI last group (phase 1, no IMI; phase 2, IMI 20 min). The main outcome measures were HbA1c, blood glucose profile, incidence of hypoglycemia, quality of life, treatment satisfaction, and patient preference. Forty-nine patients were randomized to the IMI first group and 51 patients to the IMI last group. Omitting the IMI only slightly increases HbA1c (average intraindividual difference = 0.08% [95% CI 0.01-0.15]). Since the difference is not clinically relevant, a therapy without IMI is noninferior to its application (P < 0.001). In the secondary outcomes, the incidence of mild hypoglycemia also did not differ between no IMI and IMI significantly (mean of differences = -0.10, P = 0.493). No difference in the blood glucose profile of both groups was found. Treatment satisfaction increased markedly, by 8.08, if IMI was omitted (P < 0.001). The total score of the quality of life measure did not show differences between applying an IMI or not. Insulin therapy without IMI was preferred by 86.5% of patients (P < 0.001). An IMI for patients with T2DM and preprandial insulin therapy is not necessary.