July 23, 2010
Progress in Type 1 Diabetes: Insulin Pumps with Continuous Glucose Monitoring
Before I review this week’s study, bear with me while I clear up some terms.
Type 1 diabetes mellitus and type 2 diabetes mellitus are completely different diseases. That they have such similar names and are differentiated only by a “type” promotes the common misunderstanding that they are subtypes of the same disease. They should just have different names to keep things clear. (I suggest “George” and “Bob”.) They have entirely different causes and treatments. Type 1 diabetes is caused by the body’s immune system destroying the pancreas’s ability to make insulin, the hormone that controls blood sugar levels. It tends to be diagnosed in children and young adults. Insulin is entirely absent in these patients, so insulin is the only treatment.
Type 2 diabetes is caused by hormonal changes that prevent insulin from working well. It is usually diagnosed in overweight adults. Treatments include weight loss, a low carbohydrate diet, and various medications that lower blood sugar, including insulin. Type 2 diabetes is over ten times more common than type 1, and when people just say “diabetes” they mean “type 2 diabetes mellitus”. Some type 1 patients are justifiably cranky at the public misunderstanding of their disease and at being lumped in with the greater number of type 2 patients. The only things the diseases have in common are elevated blood sugar and the complications that result from that. (The word diabetes derives from an ancient Greek term relating to a frequent symptom of elevated blood sugar – excessive amounts of urine. This is also a symptom of a third entirely unrelated disease, diabetes insipidus, which should absolutely have a completely different name, like “Fred”.)
Are you with me so far?
Well, this week’s post is about type 1 diabetes. A major struggle in type 1 is keeping blood glucoses as close to normal as possible, while avoiding hypoglycemia (abnormally low blood sugar). The standard of care for a long time has been multiple daily blood sugar measurements and insulin injections. More recently, insulin pumps have become available which infuse insulin continuously in an attempt to more accurately match the normal function of the pancreas. The most recent advance has been continuous glucose monitoring, in which a sensor displays ongoing data about the glucose level and its trend over time.
A study this week in the New England Journal of Medicine compared glucose control in child and adult type 1 patients randomized to multiple daily insulin injections versus an insulin pump with continuous glucose monitoring. The group with the insulin pumps achieved lower average blood sugars without an increase in hypoglycemia.
This advance offers the potential of minimizing the serious complications of type 1 diabetes, and will likely become the standard of care for motivated patients who can learn the intricacies of insulin pump use. The long-term goal of an artificial pancreas – an insulin pump integrated with a glucose sensor that adjusts insulin doses automatically – is now one step closer.
Wall Street Journal article: Medtronic Insulin Pump Shown To Work Better Vs Injections
New England Journal of Medicine article: Effectiveness of Sensor-Augmented Insulin-Pump Therapy in Type 1 Diabetes
New England Journal of Medicine editorial: Continuous Glucose Monitoring — Coming of Age
Important legal mumbo jumbo: