29 January 2013

Closed Loop Insulin Delivery System Improves Glucose Control And Reduces Risk of Hypoglycemia For Diabetics

Closed Loop Insulin Delivery System
Credit: BioMed Central Ltd.
A Closed Loop Insulin Delivery System improved the control of glucose levels and reduced the risk of hypoglycemia compared with conventional pump treatment in a trial published in CMAJ (Canadian Medical Association Journal).

Diabetes is a disease where the body has difficulty maintaining glucose levels in the blood. There is a problem with insulin production. Insulin is a hormone that regulates glucose levels. There is either too little insulin produced (or none at all) or that the body is rejecting it.

In type 1 diabetes, the body mistakenly identifies the insulin producing beta cells located in the pancreas as harmful and start attacking it. Because of this, type 1 is identified as an autoimmune disorder. This kind of disorder is hereditary and can be passed down through families.

Diabetes is a life long disease. There is still no cure for it. Despite this, diabetes can be managed. Regular insulin shots are done in lieu of the body's production process.

An important part of managing diabetes is monitoring one's blood glucose levels. Once the levels indicate a higher than normal glucose measurement, an insulin shot will help bring it down. It is important that the blood glucose levels being aimed for are as near normal as possible (that is in the range of those of a person who does not have diabetes).

A recent technology that combines both blood monitoring and insulin delivery is the closed loop insulin delivery system. The device continuously monitors the glucose levels in the blood and when it senses that the levels are too high, it automatically delivers insulin to the body.

Improving Diabetes Management

For patients with type 1 diabetes, a dual-hormone artificial pancreas system (also known as a closed-loop delivery system) improved the control of glucose levels and reduced the risk of hypoglycemia compared with conventional pump treatment in a trial published in CMAJ (Canadian Medical Association Journal).

It is challenging for patients with type 1 diabetes to control their glucose levels because tight glucose control increases the incidence of hypoglycemia (dangerously low glucose levels). Insulin pump treatment, which provides a continuous predetermined subcutaneous supply of insulin, is available, but hypoglycemia still occurs.

"Hypoglycemia is feared by most patients and remains the most common adverse effect of insulin therapy," writes Ahmad Haidar, Institut de Recherches Cliniques de Montréal and McGill University, with coauthors.

The dual-hormone artificial pancreas delivers insulin and glucagon using infusion pumps based on continuous glucose sensor readings as guided by an intelligent dosing algorithm. The infusion pumps and the glucose sensors are already on the market, but the intelligent algorithm was developed by the researchers in Montreal.

Video: Technology and Diabetes

Researchers sought to assess the ability of the artificial pancreas to improve glucose control and reduce the possibility of hypoglycemia in adults with type 1 diabetes. They conducted a trial with 15 adult patients who had been using an insulin pump for at least 3 months. Patients were admitted to a clinical research facility for 2 15-hour experiments, and their glucose levels were controlled in 1 visit using the artificial pancreas system and the other visit using conventional pump treatment. On each visit, the patients exercised on a stationary bike, received an evening meal and a bedtime snack, and stayed in the facility until the next morning.

With the artificial pancreas system, participants' glucose levels were in the target zone 71% of the time compared to 57% with the conventional pump treatment. The artificial pancreas resulted in a 20-fold reduction in the number of night-time glucose measurements in the low glucose level range.

"[The dual-hormone artificial pancreas] improved glucose control and reduced the risk of hypoglycemia in our 15 participants, as compared with continuous subcutaneous insulin infusion," write the authors. "Rates of hypoglycemia were reduced, with no increased risk of hyperglycemia."

"Closed-loop delivery systems have the potential to substantially improve the management of diabetes and the safety of patients. These systems will probably be introduced gradually to clinical practice, with early generations focusing on overnight glucose control and using insulin alone," conclude the authors.

In a related commentary, Drs. David Nathan and Steven Russell, Massachusetts General Hospital, Harvard Medical School, write "Although [this] study is neither the first nor the longest investigation using a dual-hormone artificial pancreas, it is the first to compare such an apparatus to conventional intensive therapy in a randomized design. Treatment with the artificial pancreas increased the amount of time patients spent in the target range of blood glucose levels and decreased hypoglycemia. Thus, Haidar and colleagues show that low doses of glucagon administered under the control of a computer algorithm can act as a counter-regulatory hormone, preventing glucose levels from falling too low."


Canadian Medical Association Journal
Glucose-responsive insulin and glucagon delivery (dual-hormone artiicial pancreas) in adults with type 1 diabetes: a randomized crossover controlled trial
The future of care for type 1 diabetes
Institut de Recherches Cliniques de Montréal
McGill University
Successful Test of Artificial Pancreas System, Hypoglycemia Hyperglycemia Minimizer (HHM) System For Type 1 Diabetes
New Study In Treating Type 1 Diabetes Involving Insulin Producing Intestinal Cells
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