Continuous subcutaneous insulin infusion leads to immediate, stable and long-term changes in metabolic control

Background:  Evaluations of continuous subcutaneous insulin infusion (CSII) usually focus on one pre- and one post-CSII measurement to assess metabolic therapy outcome. Aim:  Extending this research, the aim of the present study was to provide a more fine-grained analysis of achieved glycaemic control. Methods:  In 52 patients with type 1 diabetes (mean age of 37.85 years at CSII begin; s.d. ± 12.41), haemoglobin A1c (HbA1c) levels were assessed every 3 months over a period of 5 years (1 year before and 4 years after the introduction of CSII). Mixed models were utilized to describe changes in glycaemic control. Results:  The pre–post course showed that already in the first quarter, a statistically significant lower HbA1c level was obtained [7.30%, in contrast to 8.21% at the last quarter with intensified conventional therapy (ICT)]. In the following 15 quarters, the mean HbA1c levels remained constantly lower than that with ICT. Overall, the aggregated mean HbA1c level of patients with CSII therapy was 7.19%, in contrast to 8.08% with ICT; thus, an overall decrease by 11% was achieved. In addition, individual differences in blood glucose level and age of diabetes onset as a predictor for therapy success were analysed. Conclusions:  The data show an immediate, stable and long-term effect of CSII on HbA1c. In addition, a significant relationship between metabolic control and age of diabetes onset was found, as well as a reduction of variance in HbA1c levels between subjects after change to CSII.