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Chapter 1 Insulin Pump Therapy Advantages and Disadvantages

Karen M. Bolderman, RD, LDN, CDE

Insulin pump therapy is in its fifth decade and is gaining wider popularity. In the U.S., an estimated 20–30% of patients with type 1 diabetes and <1% of insulin-treated patients with type 2 diabetes use an insulin pump (HSBC Global Research 2005). As of this writing, the most current data indicate that there are over 375,000 patients with type 1 diabetes (up from approximately 130,000 in 2002) now using an insulin pump (U.S. Food and Drug Administration, General Hospital and Personal Use Medical Devices Panel 2010). Insulin pump therapy requires fewer “injections” compared with multiple daily injection (MDI) therapy; an infusion site is changed every 2–3 days, for an average of about 152 infusion site insertions/year, while MDI therapy results in about 1,460 injections/year (based on 4/day). Until research yields a practical way to replace lost β-cell function in diabetes, the insulin pump provides the most elegant method of insulin replacement. In its best application, pump therapy is a rare win–win situation in diabetes in terms of glycemic control and personal freedom.

An insulin pump is a wonderful diabetes management tool, but as with any tool, the pump is only as good as the patient’s ability to use it. Clinicians have a responsibility to carefully screen and provide access to educational resources to all patients who express an interest in pump therapy. When patients are mismatched with the pump or the pump regimen, loss of control may occur and potential benefits are lost or nullified.

Successful pump therapy is more likely with motivated and conscientious patients. Regardless of what many patients first think, the pump patient must perform frequent self-monitoring of blood glucose (SMBG), learn how to use their data, and understand how to use their insulin pump to ensure proper pump function and improve or achieve desired glucose control (American Diabetes Association 2004). Also, the patient must calculate food-related bolus insulin doses based on individualized insulin-to-carbohydrate ratios as well as bolus doses to decrease hyperglycemia based on individualized insulin correction (sensitivity) factors.

Insulin pump: A small, programmable, battery-powered device worn externally that delivers insulin in tiny continuous amounts (basal doses) and in larger amounts for meals or hyperglycemia (bolus doses). The pump is attached to the patient by either an infusion set consisting of long, thin flexible tubing with a catheter (or needle) on the end that is inserted subcutaneously into the patient, OR, a tubing-free (“patch”) pump is directly attached to the patient with a subcutaneous needle-inserted catheter and self-adhesive tape. The user programs and operates the pump or the pump’s remote control device to deliver insulin doses that match individual needs. An insulin pump does not automatically calculate the amount of insulin needed; patients and healthcare professionals work together to calculate the patient’s daily insulin amounts, and the pump is then programmed by the patient to deliver insulin based on the person’s specific requirements.

Benefits

For People with Type 1 Diabetes

• Improves glycemic control by delivering an individualized basal rate supplemented with bolus doses to match the patient’s intake and correct any hyperglycemia. Erratic glucose fluctuations can potentially be reduced.

• Offers precise dosage delivery in basal rates as low as 0.025 units/h and bolus doses in exact whole, tenth, and twentieth-unit doses.

• Can manage the dawn phenomenon by delivering a higher basal rate during the dawn hours.

• Can control glucose during and after exercise by delivering a lower basal rate.

• Has the potential to decrease the risk of hypoglycemia by allowing patients to individualize insulin doses to match their requirements hour by hour.

• May lessen or reverse hypoglycemia unawareness by decreasing the incidence of hypoglycemia.

• Allows incremental, precise doses to match growth spurts in children and adolescents and to manage people who are insulin sensitive.

• Improves management of patients with gastroparesis by adding the option of splitting and/or extending bolus delivery over time to match delayed absorption of nutrients.

• Can match delayed gastric emptying observed with the use of pramlintide, or with the consumption of high-fat foods, by extending bolus delivery over time.

• Eliminates the frequency and inconvenience of multiple daily injections (MDI).

• Increases lifestyle flexibility by allowing the person to eat at desired intervals instead of matching food intake to injection therapy insulin peak times.

• Improves well-being and quality of life by providing freedom in school, work, exercise, and leisure-time schedule variations.

• Allows for easier weight loss. With individualized dosing, the pump patient is not “chasing insulin” with additional food. Additionally, with decreased incidence of hypoglycemia, caloric intake to treat hypoglycemia is reduced.

For People with Type 2 Diabetes

• Allows the attainment and maintenance of improved glycemic control

• Eliminates the frequency and inconvenience of MDI.

• Increases lifestyle flexibility by allowing the person to eat at desired intervals instead of matching food intake to injection therapy insulin peak times.

• Improves well-being and quality of life by providing freedom in school, work, exercise, and leisure-time schedule variations.

• Allows for easier weight loss. With individualized dosing, the pump patient is not “chasing insulin” with additional food. Additionally, with the potential decreased incidence of hypoglycemia, caloric intake to treat hypoglycemia is reduced.

For Women Who Are Pregnant or Planning Pregnancy

• Mimics normal physiology with individualized precise dosage delivery.

• Has the potential to decrease pre- and postprandial glucose (PPG) excursions.

• May potentially reduce the risk of hypoglycemia.

• Improves the management of morning sickness by eliminating the need to eat on rising: a correctly calculated basal rate maintains euglycemia.

• Allows for easier achievement of recommended blood glucose goals.

• May potentially reduce postprandial hyperglycemia due to the delayed. gastric emptying of normal pregnancy as well as gastropathy with the use of the extended or combination bolus feature.

Myths

Patient	Healthcare Professional
The pump calculates and delivers all my insulin doses automatically	The pump calculates all the required insulin doses automatically
No more SMBG	Any patient can use a pump
Can eat whenever I want without planning	Less emphasis on meal planning
Can eat as much as I want	Not useful in type 2 diabetes
Too expensive	Too expensive
Too much trouble	Too complicated for most people
Can’t wear it during exercise, swimming, or intimacy	Can’t wear it during exercise, swimming, or intimacy
Can eliminate low and high glucose levels	Can eliminate low and high glucose levels
I can lose weight quickly by skipping meals	Will cause weight gain because most patients will start eating more, since they only have to press a button to deliver insulin instead of taking injections
Children won’t like wearing a pump	Too risky for children to use
Can learn how to use a pump in just a few minutes, since I’m very tech-savvy	A pump company representative gets the patient ready and calculates the patient’s starting basal rate(s), insulin-to-carbohydrate ratio(s) (ICR), blood glucose goals, and correction (sensitivity) factor(s) as part of the pump training

The pre-pump and ongoing education and skills training in pump use provided by the healthcare professional are crucial in correcting any misconceptions the patient may have about pump therapy and, even more important, in guiding the patient as s/he develops pump skills. The truth about pump therapy is that the greater the patient’s effort and the greater the support and access to skills training, the greater the chance that therapy will succeed. Healthcare professionals as well as patients need to understand the implications of pump therapy, including both benefits and challenges.

Challenges

Pump therapy is not without some challenges and risks, although a patient with motivation, pre-pump training, and ongoing pump education can tackle practically any drawback. However, inattention to problems can create life-threatening circumstances. Weigh these challenges and risks against the benefits.

• In putting a patient on a pump, there are challenges and risks for the healthcare professional (HCP) as well. Preparing the patient for pump therapy requires an assessment of the patient’s “readiness” and diabetes knowledge and coordination of efforts on the part of the patient, pump manufacturer, and diabetes educators. The HCP’s initial learning curve, i.e., willingness to learn pump therapy, and the time investment for patient follow-up and management are crucial factors in assuring success with pump therapy.

• A learning curve. Pump therapy requires education, skills training, and initial intensive follow-up and management. A patient contemplating pump therapy must know beforehand how to count carbohydrate and match insulin doses with carbohydrate intake and basal needs. A patient must also know his/her correction (sensitivity) factor(s) and how and when to use a corrective insulin dose. The pump wearer must learn the technical “buttonology” of their specific pump and learn how to insert the battery(ies), fill (if appropriate) and insert the insulin cartridge/reservoir, change the infusion set and tubing (if applicable), and calculate appropriate insulin bolus doses. Intensive follow-up for the first few weeks after pump initiation is essential and includes detailed recordkeeping of glucose levels, carbohydrate intake, exercise, and insulin doses. For children, the learning curve also involves their parents and caregivers.

• Frequent SMBG. The pump wearer must perform a minimum of four glucose checks daily, with additional checks as needed between meals; during sleep hours; before, during, and after exercise; during illness and at times of stress; and when glucose levels become erratic or “unexplainable.” Bolus doses of insulin must be calculated to match the person’s food intake, anticipated activity, current glucose level, and insulin “on board” from a previous bolus dose(s).

• Possible weight gain. Insulin pumps offer precise dosage delivery to match the patient’s food intake. It can become easy for the pump wearer to bolus extra insulin for additional calories. People may begin to eat foods that may have been considered “forbidden” before using a pump and may over indulge in high-calorie foods of low nutrient value. Although glycemic control can be maintained with additional insulin doses for excessive caloric intake, weight gain can result.

• Hypoglycemia. If the basal rates are not set correctly or if the pump wearer miscalculates and overdoses a bolus delivery or doesn’t compensate for exercise or for the insulin “on board” from a previous bolus dose(s), hypoglycemia can result. Pattern management is very important.

• Unexpected hyperglycemia. If the patient miscalculates or improperly sets the basal rate(s) or bolus doses, hyperglycemia can occur unexpectedly. The rare pump failure or occasional site occlusion or site “blockage” due to overuse and resultant scar tissue can decrease or prevent basal/bolus delivery, resulting in hyperglycemia.

• Ketoacidosis. In addition to the potential improper setting of the basal rate(s), the omission of filling the tubing (if applicable), and omission or miscalculation of a bolus dose, the rare pump malfunction may also cause partial or total interruption in the basal delivery. Because the pump uses only rapid-acting insulin, there is no “background” insulin available for hyperglycemia and the prevention of ketonemia. However, studies from the past three decades revealed a decrease in diabetic ketoacidosis in pump wearers compared with patients using MDI therapies (Bruttomesso 2009).

• Skin irritation and infusion site infections. People with sensitive skin may develop redness, tenderness, itching, or rashes from the infusion set or pump self-adhesive tape. Those who perspire heavily or participate in water sports may have problems with getting the tape to stick to their skin. Removing the adhesive may also cause concern. Site infections can occur from poor insertion technique or leaving the infusion set or pump (if applicable) in place too long.

• Logistics/placement. Although the insulin pump weighs about 4 oz and is smaller than a smart phone, wearing it creates challenges. Despite offering flexibility in lifestyle, many people may find it unpleasant or intolerable to be connected 24 h a day to a small external device. Pumps that use tubing to connect to an infusion set require a clip, a case with a built-in clip, or a belt-loop case for attachment. Some people prefer to place their pump in a pocket, whereas others may choose to wear their pump discreetly under clothing. Tubeless or patch pumps cannot be moved into pockets. They can be placed under clothing, but when wearing or changing clothes that do not cover or “hide” them (such as sleeveless tops or low-waisted slacks), because the pump’s adhesive is applied to the skin, the pump is immovable until the infusion set and site are changed several days later. Intimacy/sexual activity, showering or bathing, exercise, and contact sports create additional challenges in how to wear the pump.

• Medical requirements. Some insurance companies may require that a potential pump patient provide SMBG records and/or a medical necessity form completed by the healthcare professional, as well as certain lab reports (such as recent A1C or C-peptide levels) before the patient is “approved” for the purchase of an insulin pump.

• Paying for it. In 2013, the average price of an insulin pump is between $6,000 and $8,000. Disposable supplies, including pump batteries, insulin cartridges/reservoirs, infusion sets, and skin preparation products can add up to an additional $1,500 or more per year. As of this writing, a recent introduction to the pump market offers a lower initial “setup” cost but requires disposable components that may cost slightly more than standard pump supplies, thus enabling the disposable components to be covered under a patient’s insurance for supplies rather than durable medical equipment. In general, increased insurance reimbursement for pump therapy has helped to increase its use (Scheiner 2009). Some insurance companies cover all or some of the expense, whereas others may provide for only the pump and not the supplies, or vice versa. Advise your patient to be thoroughly familiar with the costs before making a commitment to pursue pump therapy. Pump manufacturers are happy to work with a potential pump patient’s insurance company to investigate coverage and out-of-pocket costs.

References

American Diabetes Association: Continuous subcutaneous insulin infusion (Position Statement). Diabetes Care 27(Suppl. 1):S110, 2004

Bruttomesso D, Costa S, Baritussio A: Continuous subcutaneous insulin infusion (CSII) 30 years later: still the best option for insulin therapy. Diabet Metab Res Rev 25:99–111, 2009

HSBC Global Research: Diabetes: proprietary survey on insulin pumps and continuous blood glucose monitoring. Healthcare U.S. Equipment & Supplies, 2005

Scheiner G, Sobel RJ, Smithe DE, Pick AJ, Kruger D, King J, Green K: Insulin pump therapy: guidelines for successful outcomes. The Diabetes Educator 35(Suppl. 2):29S–43S, 2009

U.S. Food and Drug Administration, General Hospital and Personal Use Medical Devices Panel: Insulin Infusion Pumps Panel Information, 2010