None listed
Conditions
Brief summary
Insulin delivery via an insulin pump can mimic the normal action of the pancreas more closely than multiple daily injections of short and long acting insulin. With the development of continuous glucose monitoring devices, glucose levels can be measured continuously over 24 hours. These two devices have now been linked by a computer to create an “artificial pancreas” or Closed Loop system. The computer’s function is to calculate accurately the amount of insulin to be delivered by the pump based on the sensor glucose readings. Overnight Closed Loop systems have been tested in both children and adults with Type 1 diabetes. Overall, the results show that the systems are safe and effective. However, important gaps in our knowledge remain to be explored. For example, while exercise is healthy for people with diabetes it can result in unpredictable changes in glucose levels that may challenge an artificial pancreas. In addition, different types of exercise have differing effects on glucose levels in people with Type 1 diabetes. Short intense bursts of exercise (anaerobic exercise) may initially increase glucose levels while less intense exercise (aerobic exercise) tends to reduce glucose levels. This study aims to collect information about how well the Closed Loop system is able to control glucose levels of people with type 1 diabetes when they undertake aerobic and anaerobic exercise. Outcomes of interest will include the risk of hypoglycaemia and time in healthy glucose range. Insulin and counter-regulatory hormones will also be measured providing insights into changes in glucose levels with exercise in Type 1 diabetes patients.
Interventions
This two staged randomised crossover study involves people with type 1 diabetes who are established on insulin pump therapy and have glucose sensing experience. The study aims to examine the performance of an integrated "artificial pancreas" challenged by aerobic and anaerobic exercise in people with type 1 diabetes therapy and with glucose sensor experience.
All participants will undertake the aerobic and anaerobic exercise stages in random order. Following clinical assessment, each participa
This two staged randomised crossover study involves people with type 1 diabetes who are established on insulin pump therapy and have glucose sensing experience. The study aims to examine the performance of an integrated "artificial pancreas" challenged by aerobic and anaerobic exercise in people with type 1 diabetes therapy and with glucose sensor experience. All participants will undertake the aerobic and anaerobic exercise stages in random order. Following clinical assessment, each participant will undergo cardiopulmonary testing to determine their maximal amount of oxygen consumed during exercise (VO2 max as ml/kg/min), maximal exercise capacity (Watts) and anaerobic threshold. Subsequently there will be a ~6 day run-in period when participants wear glucose sensors and the study pump (without insulin delivery from this pump), while continuing their usual insulin regimen via their own insulin pump. The aerobic exercise protocol will be conducted on a stationary bicycle with 5 minutes of warm-up, followed by 40 minutes of steady-state exercise at 20% below anaerobic threshold. The anaerobic exercise protocol is high intensity interval training with 5 minutes of warm-up, then 6 repetitions of 4 minutes of exercise at an intensity halfway between their anaerobic threshold and maximal intensity, followed by 2 minutes of rest (an additional 4 minutes rest will be provided between the 3rd and 4th repetitions). On the morning of the exercise study days, participants will have an early morning light breakfast (40g of carbohydrate), preceded by an insulin bolus via their own pump to account for the carbohydrate of the meal. The participants will commence their exercise program ~3 hours after arrival at the Clinical Trial Centre, and venous blood samples will be collected at 15 minute intervals from 1 hour prior to exercise until 2 hours after exercise completion to assess insulin and counter-regulatory hormones. Participants will resume their usual insulin regimen via their own insulin pump at the conclusion of each stage. Participants will return to the Clinical Trial Centre approximately 2 weeks later to undertake the alternate exercise regimen, preceded by the run-in period.
Sponsors
St Vincents Hospital
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
-Age > 18 years -Type 1 Diabetes (confirmed by fasting C-peptide level < 50 pmol/L) -Insulin pump therapy for at least 6 months -HbA1c < 9.0% -Experience with a glucose sensor -Established insulin pump therapy parameters -Ability to insert/change sensor -Ability to undertake exercise as per protocol
Exclusion criteria
-Requiring > 150 units of insulin/day -Diabetic ketoacidosis within the past 4 weeks -Hypoglycaemic unawareness (Gold score >4) while on Sensor Augmented Pump Therapy (SAPT) or > 2 severe hypoglycaemic episodes within the last 12 months -Pregnancy -Renal impairment (eGFR < 60ml/min/1.73m2) -Current or recent (<4 weeks) oral or inhaled steroid therapy -Dermatological conditions involving the region of device insertion -Ischaemic heart disease or peripheral vascular disease precluding exercise -Physical limitations (e.g. impaired vision) that would compromise operation of the Closed Loop system
Outcome results
None listed