Objective: Patients with type 2 diabetes most frequently use injections of premixed insulin formulations twice daily, but intensified insulin therapy may provide better control. This study was designed to compare metabolic control with three daily injections of Humalog Mix50 or premixed human insulin 30/70 (30 % regular/70 % NPH) twice daily in accordance with normal prescription practice.
Research design and methods: The study cohort of 40 patients with type 2 diabetes used a two-way, crossover design. Patients were randomized to either Mix50 at each main meal or human insulin 30/70 at breakfast and dinner for 3 months, followed by the alternate treatment for 3 months. Blood glucose was measured by the patients at baseline and at the end of each treatment sequence. No significant carryover effects were observed, so treatment sequences were combined and data analyzed by unpaired t-tests.
Results: Mean blood glucose level was significantly (p = 0.010) decreased with Mix50 but not with 30/70 (p = 0.237), and there was a significant difference between treatments at the endpoint (p = 0.035). Fasting blood glucose was increased pre-breakfast and decreased at bedtime with Mix50 but was not significantly changed pre-lunch or dinner or at any time with 30/70 insulin. Blood glucose excursions were significantly decreased with Mix50 after breakfast (p = 0.002), lunch (p < 0.001) and dinner (p = 0.037) but not significantly changed from baseline with 30/70 insulin. The decrease from baseline in HbA (1c) was significantly (p = 0.021) greater with Mix50 than with 30/70 insulin. There were no significant differences between treatments regarding incidence of hypoglycemia or adverse events.
Conclusions: In patients with type 2 diabetes, a regimen of Humalog Mix50 administered three times daily before meals maintains glucose control more effectively than premixed human insulin 30/70 administered before breakfast and dinner.