An evaluation of user acceptance and performance of a mobile real-time continuous glucose monitoring system in people with type 1 and type 2 diabetes.

This study aims to evaluate the user acceptance of a real time continuous glucose monitoring (RT-CGM) system in people with T1D and T2D treated with MDI of insulin. This study also intends to evaluate the performance of the system and the the impact it has on glycaemia. The RT-CGM system consists of a glucose sensor and transmitter and a linked study iPod displaying glucose information. The glucose sensor is inserted subcutaneously, in the abdomen region, and measures glucose in the interstitial fluid (IF) through a glucose oxidase reaction. This study is a randomized crossover study involving 20 participants (10 with T1D and 10 with T2D using MDI of insulin). Participants will undertake one week of unmasked RT-CGM system (where there will be able to see their CGM information) linked to a study iPod , and one week of masked RT-CGM system (where they will not be able to see their CGM information) linked to a glucose senor recorder (GSR), in random order. Following baseline clinical assessment, researchers will provide participants with education about study devices. Initial venous blood sampling for HbA1c and 1,5 AG will be taken. 1 hour following sensor insertion, participants will undergo frequent venous blood samples (FST) to measure plasma glucose at 20 minute intervals for a duration of 3 hours. . For the 2 week study period participants will be instructed to undertake reference capillary blood glucose measurements (a minimum of 4 times a day) and to wear the RT-CGM system continuously. For the study duration participants will be instructed to keep a diary documenting activity, diet, capillary glucose reading, insulin, and symptomatic hypoglycaemia episodes. Participants will attend a study visit on Day 8. Participants assigned to the unmasked RT-CGM arm will complete a user evaluation questionnaire. A standard meal will be provided to both groups and venous bloods for glucose will be collected from the start of the meal at 20 minute intervals for a duration of 5 hours. Two hours post-meal a second sensor will be inserted to allow for crossover of the study, where the sensor will be linked to the alternative GSR or iPod. The sensor inserted on Day 1 will be removed and collected for review of the data prior to the participants departure. On Day 15 participants will attend their final study visit. Participants assigned to the unmasked RT-CGM for the second half of the study will complete a user evaluation questionnaire. An intravenous cannula will be inserted to the cubital fossa and venous blood for HbA1c and 1,5 anhydroglucitol (1,5 AG) will be taken. Participants will then be provided a meal and have venous blood collected at this time at 20 minute intervals over the following 3 hours for plasma glucose measurements.