Glucose Variability in Subclinical Hypertrophy

Evaluation of insulin absorption at sites affected by clinically apparent lipohypertrophy through short-term continuous glucose monitoring has shown inconsistent results and it is yet unknown how or if subclinical lipohypertrophy affects absorption. In this study investigators propose to enroll at least 20 people who participated in phase 1 and who were determined to have subclinical lipohypertrophy to examine the correlation between glycemic control and amount of insulin injected in subclinical hypertrophic areas using capillary blood glucose and continuous glucose monitoring.

Patients will be randomized and data interpreters will be blinded to two alternating six-day protocols where the patients will be advised verbally and by written instruction to inject insulin in sites of subclinical lipohypertrophy or normal subcutaneous tissue. Patients will be asked to monitor and record their capillary blood glucose with meals and prior to bedtime using their own capillary blood glucose monitor. A trained research nurse at the Diabetes Centre will instrument each patient with an iPro 2 glucose sensor (Medtronic Canada). These sensors continuously measure blood glucose for periods of up to 7 days. A trained nurse will clean the skin with a superficial disinfectant and a small catheter will be inserted in the subcutaneous tissue at a non-lipohypertrophic site. The catheter will then be attached to a glucose sensor. Patients will wear this sensor for two periods of 6 days each at different sites. At the end of each of the two six day periods, the sensor will be removed.

Participants inject their insulin into the abdomen into areas of lipohypertrophy that were identified by ultrasound in Phase 1 of the study.

Inclusion Criteria: Participation in phase 1 Type 1 or Type 2 diabetes for at least 2 years Using insulin to manage diabetes At least 19 years of age Exclusion Criteria: Taking insulin secretagogues (gliclazide, glyburide, glipizide Taking other injectable diabetes medications (i.e. liraglutide, Victoza) Taking systemic steroids (e.g. prednisone) Not fluent in speaking and writing English (unless accompanied by a translator)