The impact of continuous subcutaneous insulin infusion and multiple daily injections of insulin on glucose variability in older adults with type 2 diabetes

Aims: To determine whether continuous subcutaneous insulin infusion (CSII) or multiple daily injections of insulin (MDI) are associated with improved glycemic variability. Methods: Type 2 diabetic patients ≥ 60 years of age were randomized to 12 months of CSII (n=53) or MDI (n=54) therapy. Patients were asked to complete monthly eight-point self-monitored glucose profiles (n=78) and continuous glucose monitoring systems (CGMS) for up to 72 h at Months 0, 6, and 12 (n=77). Within-day mean glucose, standard deviation (SD), range, pre- and post-prandial glucose, M value, and mean amplitude of glycemic excursions (MAGE) were calculated from eight-point profiles. Mean glucose, SD, range, area under the curve (AUC) high (>180 mg/dl) and AUC-low (<70 mg/dl) were calculated from CGMS. Mixed model analyses of variance were used to examine the associations between treatment, time, and the study outcomes, adjusting for any effects of sex. Results: With the use of the eight-point profiles, CSII and MDI groups did not differ with respect to mean glucose, mean pre-prandial and post-prandial glucose, SD, range, M value, or MAGE. With the CGMS data, there were no significant between-group differences in measures of mean glucose, range, SD, AUC-high, or AUC-low. In both treatment groups, all measures improved over time (P<.0001) except for AUC-low (P=.68) which did not change. There were treatment-by-time interactions when considering the CGMS range (P=.04) and AUC-high (P=.001), but no significant differences were found at individual time points. Conclusions: Glucose variability improved equally with CSII and MDI treatment in older patients with type 2 diabetes.