Randomized Crossover Study to Examine the Necessity of an Injection-to-Meal Interval in Patients With Type 2 Diabetes and Human Insulin

OBJECTIVE: 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. RESEARCH DESIGN AND METHODS: 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 HbA(1c), blood glucose profile, incidence of hypoglycemia, quality of life, treatment satisfaction, and patient preference. RESULTS: Forty-nine patients were randomized to the IMI first group and 51 patients to the IMI last group. Omitting the IMI only slightly increases HbA(1c) (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). CONCLUSIONS: An IMI for patients with T2DM and preprandial insulin therapy is not necessary.