Continuous subcutaneous insulin infusion therapy: long-term impact on insulin dose and body mass index

Introduction: Patients with Type 1 diabetes are at an increased risk of macro and microvascular diseases, which are often exacerbated by a raised body mass index (BMI)1,2. The relatively large subcutaneous insulin doses required for intensive insulin therapy have also been associated with unfavourable metabolic effects3. Continuous subcutaneous insulin infusion (CSII) has been shown to offer significantly reduced insulin requirements coupled with negligible weight change in the majority of patients; however, research investigating the long-term impact of CSII on the above factors is sparse4,5. Method: Medical records containing routine BMI and insulin dose measurements from patients undergoing CSII therapy at the Royal Liverpool and Broadgreen University Hospital were utilised. Data contained in these records spanning a 4 year period were added to an existing database and analysed using descriptive and bivariate correlation tests. Results: The study population consisted of 260 patients (33.8% male, 66.2% female); mean age 45±14 years. Three months after the commencement of CSII mean average insulin dose decreased from 54.5±27.5 to 43.8±17.6 units/day. It then stabilised at 45.0±19.1 units/day thereafter. Mean BMI was recorded at 26.1±5.1kg/m2 upon commencement of the therapy and remained constant over 4 years. Bivariate correlation demonstrated a significant relationship with BMI and insulin dose (r = 0.570, p