An estimated 350,000 people in the United States use insulin pumps today, and about 30,000 of those are believed to have Type 2 diabetes. Surprised? Type 2 diabetes is a progressive disease that causes many people who have it to eventually need to use insulin to control their blood glucose levels. Although many people still think insulin pumps are only for treatment of Type 1 diabetes, they can also be useful for some people with Type 2 diabetes.
According to Charles H. Raine III, MD, a diabetologist in Orangeburg, South Carolina, who himself has Type 2 diabetes and uses an insulin pump, the criteria for a good pump candidate are the same, no matter what type of diabetes a person has. In general, a good pump candidate has uncontrolled blood glucose, but also has a desire to try for better control of his diabetes, is willing to measure and document food intake and blood glucose levels, and is physically, emotionally, and cognitively able to manage a pump (or has a caregiver who is). Another important characteristic is a willingness to keep appointments with members of his diabetes care team.
Insulin pumps are pager-size devices used to deliver preprogrammed and user-adjusted doses of insulin. Depending on the brand and model, they hold between 176 and 315 units of insulin. Most people use rapid-acting insulin — options include insulin lispro (brand name Humalog), insulin aspart (NovoLog), and insulin glulisine (Apidra) — in their pumps, with a few using Regular. Instead of using an intermediate- or long-acting insulin as a background — or basal — insulin, a user simulates the pancreas’s steady release of insulin by programming the pump to automatically give small amounts of the rapid-acting or Regular insulin around the clock, based on his body’s needs. In addition to meeting basal insulin requirements, pump users also need to administer “bolus” amounts of insulin to cover the food they eat.
When a person first begins using a pump, he works with a trainer to determine his basal rates, which are rates of insulin release designed to keep his blood glucose within 30 points of his target blood glucose levels. Finding one’s basal rates involves monitoring one’s blood glucose levels around the clock (and sometimes skipping meals to see if a basal rate is set too high or too low, causing low or high blood glucose, respectively) and sending those numbers to the trainer, who will determine at what time and by how much the basal rates will be raised or lowered. Most people use several different basal rates, often an early morning rate, a daytime rate, and a nighttime rate. In the early morning, the body prepares itself to wake from sleep by pumping out counterregulatory hormones, which have the side effect of making the body more insulin resistant. Because of this insulin resistance, people usually need a little more insulin in the early morning. The daytime rate is usually set a little lower as the insulin resistance drops. The overnight rate can be set lower or higher, depending on whether you tend to wake up with low blood glucose or high blood glucose. Athletes or people who work out often may also set up rates for during and after their exercise.
The training period also helps people find their insulin sensitivity factor — the number of points that one unit of insulin will lower one’s blood glucose — and insulin-to-carbohydrate ratios, or how many grams of carbohydrate one unit of insulin will cover. (People may have different insulin-to-carbohydrate ratios for different times of day, including one for the early morning when a person may need more insulin to compensate for insulin resistance.) Knowing one’s insulin-to-carbohydrate ratio is key to determining how much insulin to bolus before a meal. Trainers will also help new users learn how to use premeal blood glucose readings to adjust insulin boluses. For instance, a high level may require the user to add a “correction dose” of insulin to a premeal bolus to help ensure that blood glucose levels are within target range two hours after the meal.