Optimization of basal insulin delivery in Type 1 diabetes: a retrospective study on the use of continuous subcutaneous insulin infusion and insulin glargine

Abstract

To compare the effects on glycaemic control after using continuous subcutaneous insulin infusion (CSII) or insulin glargine.Data were obtained from 17 diabetes outpatient clinics in Sweden, employing the same diabetes data management system. Type 1 diabetic patients using multiple dose injections were included prior to starting on either CSII (n = 563) or glargine (n = 513). The median duration of therapy was 25 months for CSII and 6 months for glargine. The comparison between the treatment modalities was carried out by multiple regression analysis and logistic regression analysis in an attempt at reducing the influence of confounding factors.The mean HbA1c decrease was 0.59 +/- 1.19% for CSII and 0.20 +/- 1.07% for glargine (P < 0.001, when assessed by logistic regression). An additional 0.1% lower HbA1c would be expected if glargine had been optimized with basal insulin 40-60% of the daily dose. The more pronounced effect of CSII was achieved with a lower daily dosage of insulin. In a multiple regression analysis with a change of HbA1c as the dependent variable, the following variables were significant: choice of treatment (P < 0.001), HbA1c prior to treatment (P < 0.001) and BMI prior to treatment (P < 0.01).Both regimes improved metabolic control, but CSII resulted in significantly higher reduction in HbA1c than after insulin glargine treatment, particularly in those individuals who had higher levels of HbA1c at baseline.