Diabetes technology trials
Like many other technologies, insulin pumps have become more advanced over the years and the current generation on the market include algorithms (or mathematical equations that are designed to reduce hypoglycaemia, hypo or low blood glucose) and increase time spent in the desired range. Much of our research as part of the Artificial Pancreas Consortium focuses on the safety and the use of these emerging technologies.
Above: The JDRF 6-step development program for the artificial pancreas. Our research team is currently evaluating devices at steps 2,3 and 4.
Predictive Low Glucose Management (PLGM) Study
The availability of a continuous glucose monitoring system (pictured above) is an important advancement in the pursuit of a fully automated closed-loop system.
The first stage of developing the PLGM system is focusing on a function to suspend basal insulin delivery for a pre-determined period if patients do not respond to alarms when the sensor detects hypo (suspend or low).
Whilst this is a major step forward, the capacity to suspend insulin delivery before hypo occurs as shown in the graph below, offers the additional advantage of reducing the actual time a patient spends hypoglycaemic. If effective and safe, this system is likely to reduce the burden of diabetes care while also allowing more intensive attempts to improve diabetes control.
An illustration of how the PLGM algorithm (known as Smartguard in the Medtronic 640g) predicts low blood glucose and suspends insulin delivery to prevent hypoglycaemia.
To test the safety of the system we used an investigational device (Medtronic Veo pump, sensor, translator and Blackberry smart phone with the algorithm) under 'in-clinic' conditions with full medical supervision at all times. We monitored the performance of the system under conditions of insulin excess (manual bolus through pump and increased basal rates) and moderate-intensity exercise. We then determined the need for hypo treatment with and without PLGM in each these different scenarios. We used these scenarios as they are commonly known to cause hypos in the lives of patients with Type 1 Diabetes. We also monitored the safety of the system by measuring ketones and monitoring plasma glucose after pump suspension. We found the system can reduce the need for hypo treatment in each of these conditions.
We are now conducting a larger home trial to determine how well the system works in daily life over an extended period of time.
At home trial
In the larger home trial, we will be using the Medtronic MiniMed 640G pump with sensors. The predictive algorithm housed in the new system can be accessed via a 'suspend before low' function. Though commercially available, there are no randomised controlled trials testing the 'suspend before low' function in real life. Ours is the first randomised control trial conducted as a multicentre trial with Princess Margaret Hospital as the lead site. Other centres in the trial are Westmead Children's Hospital in Sydney, Royal Children's Hospital in Melbourne, John Hunter Hospital in Newcastle and Women's and Children's Hospital in Adelaide.
We aim to recruit 175 participants to the trial. To be
eligible participants need to;
• have lived with Type 1 Diabetes for more than one year,
• have used insulin pump therapy for at least six months,
• be aged between 8 - 20 years and
• have an HbA1C level of less than or equal to 10 percent.
After an establishment period which provides familiarisation and confirms the eligibility of the participant to continue with the study, the participant will be randomised to either a control arm (Medtronic 640G pump + sensor) or to the intervention arm (Medtronic 640G pump + sensor + 'suspend before low' function on). The trial runs for six months and aims to compare the time spent in 'lows' with or without the 'suspend before low' function. We will also be investigating whether the system reduces anxiety regarding lows and improves quality of life.
For more information on this trial contact firstname.lastname@example.org,gov.au
Closed Loop /Artificial Pancreas studies
The development of closed loop systems, or an artificial pancreas for Type 1 Diabetes, is made up of an insulin pump, a continuous glucose monitor and a maths program or algorithm. The algorithm collects data from both the insulin pump and the continuous glucose monitor and then triggers the insulin pump to adjust the insulin dose automatically in an effort to maintain normal blood glucose levels. This is an exciting and rapidly advancing area of research.
Android based systems
The maths program, or algorithm, can be stored on a smart phone, which then can override the insulin pump to deliver insulin. In a partnership with St Vincent's hospital in Melbourne we are currently trialling this system for overnight blood glucose control. Not only are we monitoring quality of blood glucose, but we are monitoring how a good night of glucose control can effect other factors such as sleep quality and cognitive function. This trial will produce valuable data to compare with the results produced when a patient uses this system at home.
Above: Professor Tim Jones and a participant in one of our smartphone algorithm trials
The algorithm can also be loaded onto an insulin pump itself, so there is no need to carry an extra smartphone. We are currently testing a next generation pump by Medtronic in the clinic to see how well the system copes when we try to induce a hypoglycaemic episide. This test is based on our knowledge that the greatest fear diabetics have is hypoglycaemia, which is exacerbated if you lose control of your insulin delivery. In this study patients stayed in the research facility for four days and three nights. To test the system and its ability to prevent hypoglycaemia we asked participants to wear the system during a range of hypoglycaemia inducing scenarios. These included exercising for 45 minutes or over calibrating the glucose sensor to detect 'artificially inflated' glucose levels and in turn deliver more insulin. Preliminary results are encouraging. None of the patients on the trial experienced any overnight hypoglycaemia despite the exercise and inflated glucose levels.
At home testing
Pump therapy for the poorly controlled
In an exciting initiative we are trialling insulin pump therapy in adolescent patients who traditionally have struggled with their diabetes control. Potentially these patients have the most to gain from insulin pump therapy if they are motivated to change. Our work suggests that insulin pump therapy combined with comprehensive education and a strong support system can make a significant difference to the health of this group. We are studying 10 adolescents who volunteered to trial insulin pump therapy. Each of these adolescents has had an average HbA1c of less than 10% in the last six months. We will follow these patients for 12 months. Not only will we be monitoring their glucose control but we will also monitor the impact on their mental wellbeing and quality of life.
This trial aims to highlight strategies to assist and support those who struggle the most with managing their diabetes.The outcomes from this trial could potentially be applied more widely to the clinical care and education of other diabetics.