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URL:   http://www.diabetesselfmanagement.com/articles/tools-and-technology/insulin_pumps/print/

Insulin Pumps

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.

Pump basics
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.

Too many calculations, you say? Some of today’s insulin pumps will figure out bolus doses automatically based on the user’s blood glucose reading and the amount of carbohydrate he plans on consuming. To do this, the pump must be programmed with a user’s insulin sensitivity factor and insulin-to-carbohydrate ratios, and the user must still count the grams of carbohydrate in his meal himself or at least enter the foods and portion sizes into a device programmed to count the carbohydrates. Some pump companies have “married” their pump with a blood glucose meter, eliminating the need to manually enter blood glucose readings. The meter transmits readings directly to the pump via infrared or radio waves.

The pump’s insulin comes from a cartridge that is refillable with insulin from the same vials that syringe users buy. The pump is connected by flexible tubing to an infusion set (the OmniPod is attached directly to the skin) — an external plastic “hub” that is taped to the skin and a catheter that is inserted into subcutaneous tissue in any body region that is suitable for an injection of insulin (that is, the abdomen, upper arm, thighs, or buttocks). Infusion sets come in a variety of styles, with one main difference being the angle at which the catheter is inserted: Some are inserted at a 90° angle, and others at a shallower angle. It’s generally recommended that users change their infusion set every two or three days to reduce the risk of an infection. For most sets, the tubing disconnects from the hub, allowing people to go pumpless when bathing, swimming, or during intimate moments.

Pump benefits for Type 2 diabetes
Increased flexibility in scheduling daily activities such as meals, exercise, and social activities may be the main reason for you to consider using an insulin pump if you have Type 2 diabetes. There is also the potential for tighter blood glucose control and a reduced risk of diabetes complications.

Diabetes complication risk. According to the United Kingdom Prospective Diabetes Study (UKPDS), tight control of blood glucose in people with Type 2 diabetes helps to delay or prevent the development of microvascular complications such as retinopathy (eye disease), nephropathy (kidney disease), and neuropathy (nerve damage). Simply using an insulin pump is no guarantee of tight blood glucose control, of course, but studies have shown that pumps can help people to achieve control that is at least comparable to (and possibly better than) that of people on insulin injection regimens.

In addition to the benefits of tight blood glucose control, the UKPDS showed that tight blood pressure control can reduce risks of cardiovascular diseases for people with diabetes. Although high blood pressure is more of a proven contributor to heart disease and stroke than high blood glucose levels, getting better control of your blood glucose may help to reduce at least one risk factor for cardiovascular disease.

According to Philadelphia cardiologist Robert Bulgarelli, DO, people with Type 2 diabetes are assumed to have cardiovascular disease unless proven otherwise. “When your blood sugar remains high over a period of time, your lipid particle sizes and characteristics change,” he says. High blood glucose results in small, dense, LDL (“bad”) cholesterol particles that more readily contribute to the plaques at the root of heart disease. What you want, he says, is large, fluffy LDL. The National Cholesterol Education Program recommends that people with diabetes achieve LDL levels below 100 mg/dl and that people at very high risk for cardiovascular disease (such as people with diabetes who also have very high triglycerides, another blood fat) strive for LDL levels below 70 mg/dl. HDL (“good”) cholesterol loses its protective quality when blood glucose remains high. The American Diabetes Association recommends that women with diabetes achieve HDL levels higher than 50 mg/dl and men achieve HDL levels higher than 40 mg/dl. Triglyceride levels should be less than 150 mg/dl. Because tight control can be easier for some to achieve on an insulin pump, Dr. Bulgarelli is a great advocate of pumping.

Weight control. Better weight control is another potential benefit of using an insulin pump. Because the pump constantly delivers an adjustable stream of tiny amounts of insulin, the chances of developing hypoglycemia (and the resulting need to eat to raise low blood glucose) are reduced. There is also no need to eat to “feed” insulin peaks (such as those that occur when taking an intermediate-acting insulin such as NPH) even when one’s not hungry. The calories consumed to treat (and sometimes overtreat) or prevent low blood glucose add up, so the reduced risks of lows can help keep weight off.

Generally speaking, less insulin is used with a pump than with injections. In fact, trainers typically drop the total daily dose of insulin used by an individual by about 25% when he starts using a pump because the small amounts of insulin from a pump are absorbed more consistently than insulin from one or two large injections. Needing to use less insulin overall is also associated with better weight control. However, attention to diet remains important.

Flexibility. In a study published in the September 2003 issue of the professional journal Diabetes Care, people with Type 2 diabetes used either a pump or multiple daily injections for blood glucose control. Those using a pump reported greater satisfaction than those on multiple daily injections in all areas measured, citing less life interference, more general satisfaction, greater flexibility, and more convenience.

The flexibility offered by a pump goes beyond the obvious advantage of not having to carry around an insulin vial and syringes. Because basal insulin is being constantly delivered by the pump, users are not chained to eating or exercising at certain times to match any peaks in intermediate-acting insulin. Basal rates can be increased during times of stress or illness or decreased for some spur-of-the-moment exercise.

You don’t even have to eat at all on a pump. The first day I used a pump was a very busy — and tiring — day. When I got home, I was too tired to fix dinner, and I was not hungry. So I skipped dinner. I checked my blood glucose about every half an hour, in increasing wonder and fascination that I wasn’t going low — the inevitable result of skipping a meal when I was on multiple daily injections. My trainer was mildly horrified, and I will say that it is not recommended that you skip a meal on your first day pumping.

Getting a pump
Insulin pumps cannot be bought off the shelf; you need a physician’s letter to get one. However, many doctors are not familiar with insulin pumps, and even some who readily prescribe pumps to people with Type 1 diabetes may be reluctant to prescribe one for a person who has Type 2 diabetes. According to Rem Laan, former director of marketing for insulin pump maker Disetronic (since acquired by Roche), “Of the 25,000 doctors in the United States who prescribe insulin, only about 2,000 prescribe pumps.” Those who prescribe pumps are more likely to be endocrinologists, so you may need to see an endocrinologist to get one, and you may need to learn to be persuasive if the doctor you see does not already prescribe pumps for people with Type 2 diabetes.

The cost of a pump and pump supplies can also be an obstacle. A pump costs about $5,500, and supplies cost about $100 per month. A portion of the cost of both pump and supplies is generally covered by a person’s health insurance. My first pump was covered at 80% and the company let me make payments on the remainder. Only $2,500 of my second pump was covered, but the company gave me a discount and let me pay off the balance. Some insurance covers all of the cost of supplies, some only a percentage, and others may pay nothing. Medicare initially only offered coverage of pumps for people with Type 1 diabetes in 2000, but because of a change made in 2002, people with Type 2 diabetes with low or low-normal C-peptide levels also qualify. (Low C-peptide levels indicate reduced insulin production by the pancreas.)

If the monthly cost of supplies has you gasping, consider it in relation to the cost of oral diabetes therapy. Taking a sulfonylurea such as glipizide (Glucotrol) may cost about $32 per month, and the maximum dose of metformin can run up to $55 per month. A month’s worth of pioglitazone (Actos) at the maximum dose will set you back up to $125. Even paying only insurance copayments rather than full price can get expensive because people rarely take only one oral diabetes medicine. Adding up the costs of your drug therapy can help you make an informed, cost-effective choice between oral therapy and an insulin pump.

Check your insurance policy. If it does not specifically prohibit insulin pumps, it should cover one for you. You may have to argue your case, so be sure to keep careful records of your conversations with the insurance company, recording the people you talked to, when you called, and what you were told. This is also where the pump company of your choice will come in handy. Pump companies are very adept at negotiating with insurance companies for coverage.

A pump for you?
If you are motivated and willing to take on some additional responsibility for your diabetes care, an insulin pump could be a useful option for you. Its power and flexibility could help you to achieve tighter blood glucose control. To learn more about pumps, click here.



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