4 The diagnostic tests

4 The diagnostic tests

The interventions

MiniMed Paradigm Veo system

4.1 The MiniMed Paradigm Veo system (Medtronic) is an integrated sensor‑augmented pump therapy system that has 3 components:

  • An Enlite glucose sensor that is placed under the skin to continuously measure the glucose levels in interstitial fluid (the thin layer of fluid between blood capillaries and the body's cells).

  • An insulin pump that delivers insulin continuously to the subcutaneous tissue through an infusion set.

  • A MiniLink non‑implanted transmitter that sends glucose‑level readings wirelessly from the sensor to the pump.

4.2 The system produces an alarm sound if glucose levels become too high or low, if levels are rapidly changing, or if the system predicts that levels will be too high or too low in the near future. It has an automated low‑glucose suspend function that works independently of user action and stops insulin delivery for 2 hours if there is no response to the alert.

4.3 The system is intended to be used with standard capillary blood glucose tests because the sensor measures interstitial glucose levels rather than capillary blood glucose levels. Because glucose moves from the capillaries to tissues, there is a lag between blood and interstitial glucose levels of at least 15 minutes and so a minimum of 2 capillary blood glucose tests per day are needed for calibration. The lag increases when blood glucose levels are changing rapidly, so although trends in interstitial glucose are representative of blood glucose changes, absolute interstitial glucose values do not always match blood glucose levels. Further capillary blood glucose tests may be needed to confirm the value displayed on the pump by the continuous glucose monitor, before making any adjustments to diabetes therapy.

4.4 The insulin pump in the system continuously delivers insulin from a storage reservoir through an infusion set, consisting of thin plastic tubing and a cannula that is placed under the skin. The pump can be programmed to deliver a basal rate of insulin throughout the day, with higher infusion rates triggered by pushing a button on the pump at meal times. The higher infusion rate may be a bolus dose (that is a dose taken specifically at meal times to keep glucose levels under control after a meal) or periodic doses over a period of time. It can also deliver different basal rates of insulin at different times of the day and night. The company's instructions for use state that the infusion set and reservoir should be replaced every 2 to 3 days.

4.5 The MiniMed Paradigm Veo system is compatible with the CareLink software platform (Medtronic), which is designed to allow users to upload their data from the MiniMed Paradigm Veo system so that clinicians can evaluate the person's glycaemic control, notice any trends and adjust their therapy as appropriate.

Vibe and G4 PLATINUM CGM system

4.6 The Vibe and G4 PLATINUM CGM system is an integrated sensor‑augmented pump system that has 3 components:

  • The Vibe CGM‑enabled insulin pump (Animas) that delivers insulin continuously.

  • The G4 PLATINUM sensor (Dexcom) that continuously monitors interstitial glucose levels.

  • A non‑implanted transmitter (Dexcom) that sends glucose‑level readings wirelessly from the sensor to the pump.

4.7 The sensor is placed under the skin and measures interstitial glucose levels. It is approved for up to 7 days of use. The system produces glucose‑level readings in real‑time and glucose trend information. There is an alarm that alerts the user if the glucose levels become too high or too low, or if the levels are rapidly changing. The system also has a default low‑glucose alarm that cannot be altered by the user. It does not have an automated low‑glucose suspend function. There is a lag between blood and interstitial glucose levels of at least 15 minutes and so at least 2 capillary blood glucose tests per day are needed to calibrate the system, before making any adjustments to diabetes therapy.

4.8 The insulin pump in the Vibe and G4 PLATINUM CGM system delivers insulin continuously from a storage reservoir through a cannula placed under the skin. The pump can be programmed to deliver a basal rate of insulin throughout the day, with the option of triggering higher infusion rates at meal times, either as a bolus dose or over a period of time. The pump can also be programmed for different basal rates of insulin at different times of the day and night.

4.9 The Vibe and G4 PLATINUM CGM system is compatible with Diasend, a software platform that allows users to upload data from their pump for interpretation, to adjust settings and to keep a food database. Users can share their data with healthcare professionals, who can then use it to assess glucose trends and inform changes in therapy.

The comparators

4.10 To reflect the combinations of technologies that may be used by people with type 1 diabetes to monitor blood glucose levels and administer insulin therapy in current practice, 4 comparators are included:

  • capillary blood testing with continuous subcutaneous insulin infusion

  • capillary blood testing with multiple daily insulin injections

  • continuous glucose monitoring with continuous subcutaneous insulin infusion (non‑integrated devices)

  • continuous glucose monitoring with multiple daily insulin injections.

  • National Institute for Health and Care Excellence (NICE)