Local heating at the insulin injection site by the use of the InsuPad is able to reduce post-prandial glucose excursion in daily life

Abstract

Background and aims: The insulin action profiles of subcutaneously injected short acting insulin analogues are still slow compared to physiologically released human insulin. Thus, postprandial glucose excursions cannot be avoided. InsuPad is a medical device designed to accelerate insulin delivery rate by applying local heat at the insulin injection site. Whenever an insulin injection is given, the skin surface temperature is heated up locally to 38.5 C° for 30 minutes. This pilot-study examines the impact of the InsuPad use on postprandial glucose excursions after breakfast and dinner in daily life conditions. Materials and methods: Insulin resistant diabetic patients were instructed to use the InsuPad when injecting bolus insulin prior to breakfast and dinner for one month and to measure their blood glucose at least five times per day (pre- and post-breakfast, pre-lunch and pre- and post-dinner). In the other study phase patients were instructed to maintain the same blood glucose measurement schedule for one month, without using the InsuPad. The order of the study phases was randomized. All blood glucose data were transmitted to a central computer using the DIASEND System. A valid pre-post-prandial measurement time difference was 75 - 135 minutes. An ANOVA, controlling for order of study phase, patient and meal (breakfast vs. dinner) was used to analyze the effect of the InsuPad on postprandial glucose excursions. In this study 10 diabetic patients took part (30% type 1 diabetes, age: 51.5 ±7.7 yrs., diabetes duration: 15.7 ± 7.7 yrs.; HbA1c: 8.2 ± 0.9%; bolus insulin dose: 51.7 ± 22.2 insulin units per day; total insulin dose 0.92 insulin units per kg). Results: Preprandial blood glucose levels were similar in the phase with (151.7 ±46.8 mg/dl) and without the InsuPad (148.5 ±38.6 mg/dl, p=.385). Postprandial glucose decreased by 0.05 ± 59.1 mg/dl, if InsuPad was used, whereas the postprandial glucose levels increased by 11.3 ± 56.3 mg/dl if the InsuPad was not used (p=.011). The number (283 vs. 257) and proportion of valid measurements (65.5% vs. 64.4%, p=.740) in the phase with and without InsuPad were highly comparable. The time differences between pre- and post-prandial glucose measurements were very similar in both study phases (102.7 ± 19.0 vs. 102.3 ± 15.6 minutes with and without InsuPad, p=.777). The overall glycaemic control (mean total blood glucose values) was significantly lower when using the InsuPad compared to the no-use-phase (149.7 ± 54.5 mg/dl vs. 158.7 ±57.7 mg/dl; p=.016). The percentage of hypoglycaemic (< 60 mg/dl) or hyperglycaemic values (> 300 mg/dl) was slightly decreased when using the InsuPad, but the difference was not statistically significant (% hypoglycaemic values 1.5% vs. 1.8%, p=.496; % hyperglycaemic values 1.6% vs. 2.1%, p=.250). Conclusion: This pilot-study indicates that local heating of the insulin injection site in insulin resistant diabetic patients by using the InsuPad is able to reduce post-prandial blood glucose excursions as well as mean daily glucose values significantly in daily life conditions. Safety parameters like the prevalence of hypoglycaemic and hyperglycaemic glucose measurements were not affected by the use of InsuPad