Hypo-METRICS: Hypoglycaemia - Measurement, ThResholds and ImpaCtS

Hypoglycaemia or low blood glucose, and its fear are major barriers to achieving optimal glucose control. New technology, such as continuous glucose monitors (CGM), help to better identify hypoglycaemia and develop strategies to avoid it. These devices measure glucose in the skin, rather than in the blood, and provide information not only on how low glucose is, but also for how long. Recent studies showed that over half of episodes of low glucose with these systems are not recognised by people with diabetes, and even people without diabetes have sensor values that are below the current thresholds for hypoglycaemia \[ low blood glucose\] that we measure with traditional monitors.

In this study, the investigators will evaluate the impact of symptomatic as well as asymptomatic episodes of low sensor glucose on a variety of clinical, patient-related and health economic outcomes such as mood, quality of sleep and productivity. The investigators will test different levels and durations of low sensor glucose to identify the one that best matches episodes that are symptomatic to best define hypoglycaemia using these systems.

The investigators will also look at factors that influence this such as sleep or activity as well as diabetes management behaviours (such as insulin dosing, carb counting, etc). At the end of this study, the investigators will be able to provide a better definition of clinically relevant low sensor glucose readings that will help inform clinical as well as academic interpretation of CGM data.


Eligibility Criteria:
Inclusion Criteria:

1. Age 18 - 85 years
2. HbA1c 5 - 10% \[31 - 86 mmol/mol\]
3. Confirmed diagnosis of type 1 or type 2 diabetes
4. Using \> 1 injection of insulin / day or insulin pump.
5. Ability to provide written informed consent
6. Performing regular SMBG \[ \> 1 / day on a 4-week download\] . For those using flash or continuous glucose monitoring, this should be used at least 70% of the time.
7. At least 1 episode of hypoglycaemia \[ either biochemical or symptomatic\] in the last month
8. On stable therapy for at least 3 months.
9. Willing to complete study procedures including wearing the Fitbit and CGM devices and completing the EMA questionnaires on the uMotif app three times a day for 10 weeks ( we expect minimum 80% data completeness)

Exclusion Criteria:

1. Concurrent conditions that can affect glucose readings \[renal impairment GFR \< 30 ml/min, hepatic impairment, untreated adrenal or thyroid insufficiency, as judged by the investigator.
2. Severe cognitive impairment or psychological illness that can impair performance of EMA tasks, visual impairment that will preclude use of the EMA or sensors.
3. Severe psychiatric / psychological illness including extreme fear of hypo- or hyper- glycaemia ( in the opinion of the investigator)
4. Pregnant or plans for pregnancy in the next 6 months
5. Use of automated insulin delivery systems such as closed loop or automated threshold suspend or predictive low glucose suspend insulin pumps.
6. Known allergies to adhesives required for the CGM systems
7. People who work regular night shifts
8. Any other condition which in the opinion of the study team would impair their ability to complete the study