Advantages of Insulin Pens.
Illustration of Two Insulin Pumps.
Continuous Subcutaneous Insulin Infusion (CSII)
Size - 3.0" x 2.0" x .76" (Smaller than a business card)
Weight - 3.03 oz (with battery)
Illustration of a New Insulin Inhaling Device.
This smaller insulin inhaler device has not yet been approved for use in this country.
Exubera® is a rapid-acting, fine dry-powdered insulin that enters the bloodstream very rapidly. It is especially indicated for pre-meal insulin administration. Exubera® is dispensed in 1 mg (equivalent to 3 units of regular insulin) and 3 mg (equivalent to 8 units of regular insulin) blister packs.31 Studies have shown that people like using inhaled insulin and feel that it gives them a better quality of life, which may help them accept more intensive insulin treatment. Although inhaled insulin acts rapidly, only a small percentage of the inhaled insulin actually reaches the bloodstream. Large amounts are therefore needed and much is wasted, which explains its relatively high cost. Safety also remains a concern.
Although inhaled insulin acts rapidly, only a small percentage of the inhaled insulin actually reaches the bloodstream. Large amounts are therefore needed and much is wasted...
In general, studies have found Exubera® to be as safe as other treatments; the most common problems were hypoglycemia, cough and bitter taste. As Exubera® may affect lung function, people using it need to have their lungs tested before starting the medication, and then every 6 to 12 months thereafter. Exubera® is not recommended for people who smoke, recently quit smoking or who have chronic lung disease, such as asthma, chronic obstructive pulmonary disease or emphysema. There are other non-injectable delivery systems currently being investigated.
Fixed combinations insulins
are commercially prepared mixtures of basal and bolus insulins. While they serve a purpose, especially in people who require a simpler and more convenient method of insulin replacement, they can make precise control of blood sugar levels harder to achieve.5 Novolog 70/30, for example, is a fixed combination (70% of protamin aspart suspension and 30% soluble aspart insulin; all recombinant DNA human insulin) that is given twice daily before breakfast and dinner at a prescribed dose without self-adjustment. While simpler to implement, this type of regimen is associated with long-term weight gain and low blood sugar and is often used as a transitional preparation for a more individualized basal bolus regimen; as the name suggests, "fixed combinations" limit individualization and flexibility.
Pramlintide acetate (Symlin®) is a synthetic analogue of human amylin, a hormone secreted by the pancreas simultaneously with insulin in response to eating. Amylin slows gastric emptying, reduces post-meal rises in blood sugar and improves A1C values. The FDA has approved pramlinitide for use in people with Type 1 and Type 2 diabetes. This non-insulin, injectable amylin analogue is administered by injection before meals. It cannot be mixed with insulin in the same syringe and in patients with Type 1 diabetes is used in addition, not instead of, pre-meal insulin bolus injections.37,39 Low blood sugar levels and nausea that generally disappears with time are the most commonly reported side effects.
Medical Nutritional Therapy
Just as there is no single medical regimen that fits all people, there is no single diet that can be prescribed to everyone with Type 1 diabetes. Integrating insulin therapy with an individual's food and activity preferences is key for the management of Type 1 diabetes.
A person with Type 1 diabetes must learn how to manage hypoglycemia not only for immediate safety, but also because fear of hypoglycemia can get in the way of successfully managing blood sugar levels in the long term. Some people with this problem overeat and administer inadequate insulin in order to avoid hypoglycemia. This is not healthy. People with Type 1 diabetes need to master a fine balance between food, exercise and medications.
A person with Type 1 diabetes must learn how to manage hypoglycemia not only for immediate safety, but also because fear of hypoglycemia can get in the way of successfully managing blood sugar levels in the long term.
An important part of self-management is blood glucose monitoring. There are many types of blood glucose monitoring devices; all are fast and accurate when used correctly. Choosing one is based on individual preference and insurance reimbursement. For instance, a meter with a larger display may be better for the elderly or those with visual impairment. The toll-free 800 number on the back of each monitor is useful for trouble shooting. Frequency and timing of testing need to be individualized according to the insulin regimen and any changes in therapy. For instance, a person with Type 1 diabetes who requires 4 injections or more will need to monitor at least 4 to 8 times daily, while a person with Type 2 diabetes requiring basal insulin only may not need to check their blood sugar more often that once or twice daily. Target blood sugar ranges need to be reviewed and written down; record-keeping is a skill that when done properly helps health care providers to interpret insulin effects and make adjustments in treatment, the main reason why frequent monitoring is prescribed.
Bolus dosing before meals requires learning how to count carbohydrates. Carbohydrates are counted for the purpose of determining the correct pre-meal dosage of rapid-acting insulin. The carbohydrate content of food can be found on a food label, in a carbohydrate counting book or by learning that fixed serving sizes for each carbohydrate food contains a fixed amount of carbohydrate. For example, one small fruit or half a large piece of fruit each contains 15 grams.
There are two things to remember when carbohydrate counting. First, carbohydrate is the main nutrient that impacts blood sugar (glycemic index), not protein or fat. A large meal of bacon and eggs has minimal carbohydrate content and, therefore, little impact on blood sugar. Second, the blood sugar rise is much more related to the total amount of carbohydrate than to the source of carbohydrate. For example, two slices of bread and six Mini Tootsie Rolls each have the same carbohydrate content; therefore, each raises blood sugar levels about the same amount. Blood sugar control can be achieved regardless of the amount or type of carbohydrate eaten, as long as the proper amount of insulin is taken. The most common carbohydrate counting mistakes are identifying carbohydrate sources incorrectly, estimating portions incorrectly, misreading labels and careless snacking without administering insulin.
Individuals vary considerably in the amount of insulin needed for a fixed amount of carbohydrate. A commonly used method for estimating a person's carbohydrate to insulin ratio (CIR), the amount of carbohydrate that one unit of rapid acting insulin will cover, is to divide 500 by the average number of total daily units of insulin (rapid and long-acting) administered each day.33 Someone taking 30 units of insulin per day would have a CIR of about 1:15 (500 divided by 30 equals 16.6). In other words, 1 unit of rapid-acting insulin is needed for 15 grams of carbohydrate.
Target blood sugar ranges need to be reviewed and written down; record-keeping is a skill that when done properly helps health care providers to interpret insulin effects and make adjustments in treatment...
Factors that affect insulin sensitivity can change an individual's CIR. For instance, exercise will improve insulin sensitivity. An individual with a CIR of 15:1 who anticipates eating 2 cups of rice (90 grams of carbohydrate) needs 6 units of rapid acting insulin. Once exercise is discontinued, the individual's sensitivity may decrease and the same 2 cups of rice would now require more insulin. A rise in blood sugar from a meal of more than 50 mg/dl may be a sign of either incorrect carbohydrate counting or an incorrect CIR.
In addition to the insulin dose needed to cover the carbohydrate, a supplemental dose may be required to correct for a high pre-meal blood sugar. This dose is referred to as the correction factor (CF) or the amount that one unit of insulin can be expected to decrease the level of glucose. The CF can be estimated by dividing the total number of units of daily insulin into 1500. An individual with a target pre-meal blood sugar of 100 mg/dl whose CF is 40 (1 unit of rapid acting insulin drops the blood sugar 40 mg/dl) and whose pre-meal CBG is 180 mg/dl, needs an additional 2 units above and beyond the amount of insulin calculated to cover the anticipated amount of carbohydrate.
For those who find advanced carbohydrate counting too difficult, a fixed dose regimen can be provided. This, however, imposes the challenge of consistency in timing and carbohydrate content of meals.
Without detailed blood sugar, food, exercise and insulin-dosing records, it is difficult for health care providers to identify problems and make appropriate changes in treatment. Meaningful and engaged office visits are also very important. The rigor of intensive insulin therapy demands repeated visits to a person's healthcare provider or providers. Intensive insulin therapy also requires multiple visits to a registered dietitian during the first three months totaling 3 to 4 hours, as well as 4 to 6 additional hours of follow-up during the year. Attention to dietary management of lipids, blood pressure and weight require additional visits.
Continuous Glucose Monitoring Sensor (CGMS)
CGMS is used when more intensive monitoring is needed. A glucose sensor, placed under the skin, measures blood sugar every 10 seconds; these values are averaged every five minutes.34 The results are downloaded to a computer where graphs and tables reveal glucose trends. This device can be especially helpful in complicated situations such as hypoglycemia unawareness, gestational diabetes, preconception, pregnancy and lactation, where tighter control is needed.
Recently, Medtronic MiniMed has received approval for a new version of the CGMS, the Guardian RT. This system displays real time glucose values every 5 minutes and sounds an alarm or vibrates if glucose levels go too high or to low. The Guardian RT is approved for people 18 years of age or older who have Type 1 or Type 2 diabetes. By obtaining frequent glucose values, individuals can more readily see the effect of diet, exercise and medications and make the needed changes that will result in fewer glucose excursions. In this case, CGMS may help to assess the effectiveness of basal and bolus insulins.
Continuous Subcutaneous Insulin Infusion (CSII)
CSII is a method of delivering insulin through a motor driven reservoir that provides a constant subcutaneous insulin delivery into the body; the same insulin serves as both basal and bolus. All rapid-acting insulin analogues are more effective than regular insulin in insulin pumps — they achieve better reductions in post-meal blood sugar and provoke fewer episodes of hypoglycemia compared with regular insulin.35,36 The basal insulin consists typically of 40-60% of the total daily dose and is individually programmed and adjusted by 0.05 units every 30 minutes to match the changes in basal needs throughout the 24-hour day. Insulin delivered via CSII is absorbed better and more predictably than insulin delivered in multiple daily injections (MDI).
The pre-meal bolus insulin amount can be automatically calculated by programming the pump with pertinent numbers including the individual's carbohydrate to insulin ratio, correction factor, glycemic targets and duration of insulin action. The user enters the anticipated carbohydrate amount and blood sugar. The calculation takes into account the active insulin on board, subtracting this insulin from the estimated correction dose. Pumps also feature bolus delivery over an extended period to match prolonged digestion and absorption of food. For example, a high fat meal treated with an injection of rapid-acting insulin often results in an initial hypoglycemic response followed by hyperglycemia when the food finally is finally absorbed.
Studies comparing MDI to CSII have found that in general they produce comparable A1C values, though people on CSII report less hypoglycemia and better quality of life. Some disadvantages of the insulin pump are the higher cost for the pump and its supplies, increased skin infections and greater chance of mechanical problems such as interruption of insulin flow or pump failure that can lead to diabetic ketoacidosis (DKA). An early malfunction that is not recognized can lead to DKA within 4 to 6 hours. Therefore, it is imperative for anyone using an insulin pump to test their blood glucose levels frequently (no fewer then 4-6 times each day), be properly trained in the use of the pump, and learn how to recognize and treat acute complications.
It is important that those who choose the pump as a delivery system clearly understand that the convenience of no injections is offset by many other responsibilities and that the pump is a delivery system that is only as effective as its user. A surgically-implanted programmable insulin pump, which delivers insulin directly into the body, is under investigation. At this time, technical problems have been a barrier to approval.
Successfully managing individuals with Type 1 diabetes with a basal-bolus regimen is tricky and requires a team effort that includes the nurse, dietitian, endocrinologist and others. This labor-intensive endeavor needs to be monitored and adjusted, through trial and error, to the complex and varying needs of each individual. A variety of insulins including the more recent analogues do a better job of insulin replacement than conventional types, with the majority of people being treated with a basal-bolus regimen. Proper adjustments of bolus insulin need to be made according to carbohydrate counting and the body's constantly varying insulin sensitivity.
Recently, the FDA has approved an injectable non-insulin medication amylin analogue, and a non-injectable inhaled insulin. The wide choice of new medications and gadgetry include pen syringes, insulin pumps, and better systems for monitoring, all of which have made the management of Type 1 diabetes easier. These advances have improved insulin administration and adherence, reduced episodes of hypoglycemia and fostered a better quality of life for those with Type 1 diabetes, but they have only had a modest impact on overall control of blood sugar levels.
The Continuous Glucose Monitoring Sensor (CGMS) is slowly evolving into a closed loop system where glucose sensors will provide feedback to implantable insulin pumps so as to deliver insulin more precisely. It must always be remembered, however, that successful outcomes require effective team management by health care providers, along with an individual who is educated and motivated enough to assist in the management of their own disease.