Insulin and Type 2 Diabetes
If your health care provider offered you a medication to help you feel better and get your blood sugar under control, would you try it? If so, you might be ready to start taking insulin.
Does insulin immediately make you think of type 1 diabetes? Think again. Between 30 and 40 percent of people with type 2 diabetes take insulin. In fact, there are more people with type 2 diabetes who take insulin than type 1 because of the much larger number of people with type 2. Experts believe even more people with type 2 should be taking insulin to control blood sugar -- and the earlier, the better. With an increase in people developing type 2 at a younger age and living longer, more and more people with type 2 will likely be taking insulin.
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"If you live long enough with type 2 diabetes, odds are good you'll eventually need insulin," says William Polonsky, Ph.D., CDE, associate clinical professor of psychiatry at the University of California, San Diego; founder and president of the Behavioral Diabetes Institute; and author of Diabetes Burnout: What to Do When You Can't Take It Anymore (American Diabetes Association, 1999).
Producing Less Insulin Naturally Over Time
Research has shown that type 2 diabetes progresses as the ability of the body’s pancreatic beta cells to produce insulin dwindles over time. Your beta cells -- the cells in the pancreas that produce insulin -- slowly lose function. Experts believe that by the time you're diagnosed with type 2 diabetes, you've already lost 50-80 percent of your beta cell function and perhaps the number of beta cells you had. And the loss continues over the years.
"About six years after being diagnosed, most people have about a quarter of their beta cell function left," says Anthony McCall, M.D., Ph.D., endocrinologist and James M. Moss Professor in Diabetes at the University of Virginia School of Medicine. "With this minimal function, the need for injected insulin increases."
Some experts say initiating insulin or other blood glucose-lowering medications early in the course of type 2 diabetes can lower blood glucose and even preserve some beta cell function.
Insulin resistance is another consistent factor in type 2 diabetes. This refers to the body's inability to effectively use the insulin you make. So type 2 diabetes becomes a twofold problem even at diagnosis: not enough insulin is being made, and too little of the insulin that is made can effectively lower blood sugar. To treat insulin resistance, most guidelines recommend starting with a drug called metformin at diagnosis. Metformin is commonly used because is treats the insulin resistance, and it's safe, reliable, effective, and available generically so it’s relatively inexpensive.
Making the Most Out of Your Own Insulin
To stay healthy with type 2 diabetes over the years, the key is controlling your blood sugar, blood pressure, and blood lipids (cholesterol). These are the so-called ABCs of diabetes care -- A is for A1C (average blood glucose), B for blood pressure, and C for cholesterol (blood lipids). To control blood sugar, you need to continually and progressively be adjusting your diabetes care to compensate for your body's waning supply of insulin and growing level of insulin resistance.
At diagnosis, some people still produce enough insulin to hit their blood sugar targets by eating healthfully, getting physical activity, and losing weight. In fact, losing 10-20 pounds can make a dramatic impact early on. But research shows that most people need to start diabetes medications and/or insulin right away.
As the body gradually produces less insulin, nearly everyone with type 2 diabetes needs one or more oral or injectable blood glucose-lowering medications, which might include insulin. Additionally, there is now a category of blood glucose-lowering medicines called incretin mimetics or GLP-1 analogs that are injectable: Byetta, Victoza, and Bydureon are the three approved brands.
When you start insulin or any blood glucose-lowering medication, you still need to eat healthfully and be physically active.
Where Manufactured "Human" Insulin Comes In
The goal of taking insulin injections is to mimic your body's normal insulin response. People who take insulin most likely will eventually need a combination of rapid- or short-acting and long-acting insulins to mimic normal insulin function and to control blood glucose.
A normal pancreas releases insulin constantly, not just when you eat, says John Walsh, P.A., CDE, coauthor of Using Insulin: Everything You Need for Success with Insulin (Torrey Pines Press, 2003). Adults produce about 1 unit of insulin per hour. This is called basal insulin or background insulin.
In response to food, insulin is released from the pancreas in two phases:
1. The first burst occurs within 15 minutes of your first bite in response to rising blood glucose.
2. The second phase happens more slowly, over the next one-and-a-half to three hours, to match the rise in blood glucose from the food you ate, which is called bolus insulin or mealtime insulin.
The Fear Factor
Many people are afraid to start taking insulin, which is understandable.
"This is the moment at which type 2 diabetes becomes real," says William Polonsky, Ph.D., CDE. "Some people believe that starting insulin means their health will worsen. Others fear the injections themselves or are anxious about the disruptions, inconveniences, and changes taking insulin will cause."
Many people also worry about hypoglycemia (when blood glucose falls below 70 mg/dl and you feel dizzy or shaky). Low blood sugar can happen, but statistics from studies show it's rare in people with type 2 diabetes.
Polonsky, who speaks internationally to health care providers about effective ways to help people start insulin, says providers often escalate these fears by positioning the need for insulin as a punishment for a person's failure to make lifestyle changes to control blood sugar. In reality, the problem is beta cell failure that happens in most everyone during the course of type 2 diabetes.
Face Your Fears
Be honest with your health care providers about any concerns you have about taking insulin.
"Get the facts you need about taking insulin in the 21st century," says endocrinologist Anthony McCall, M.D., Ph.D. He says many fears are due to dated knowledge, observations of older relatives who have taken insulin, and lack of awareness about the current devices and needles used to take insulin.
Taking insulin today is nearly painless. Insulin pens and syringe needles are slimmer, shorter, and sharper than ever before.
When to Start
How do you know you need insulin, and how should you start taking it?
"You need insulin if your A1C is higher than 6.5 or 7 percent, despite eating healthfully, being active, and taking several other blood glucose-lowering medicines in effective doses," says McCall.
If your blood sugar levels are above 250 mg/dl and A1C is above 9 percent, then insulin is the only available therapy that will lower your blood sugar levels enough. If you gain better control, you may be able to manage your diabetes with other blood glucose-lowering medicines (and without insulin) for a while. It’s also possible that over the years you might need insulin intermittently, such as during a hospitalization or if you have an infection or need to take a steroid medication for a period of time. Insulin is the only blood glucose-lowering medication that you can take as much as your body needs to control your glucose levels.
Blood Glucose Goals
American Diabetes Association
American Association of Clinical Endocrinologists
Blood glucose (plasma values)
2 hours after the start of a meal
< 110 mg/dl
Lab test of average blood glucose
How to Start Taking Insulin
Your health care provider can start you on insulin in one of several ways: You may begin with a simple regimen, such as one injection of intermediate- or long-acting insulin at night, or a combination insulin, such as a 70 percent long-acting and 30 percent rapid-acting mixture, at breakfast and dinner. Mixtures in other ratios are also available. Individual insulins and combination insulins can be taken using vials and syringes or insulin pens. Using an insulin pen is easier to dose, potentially more accurate, and a more convenient way to carry your insulin. (The insulin in either a vial or pen can be at room temperature for up to 30 days. It doesn't need to be refrigerated. However, you should store extra insulin in the refrigerator.)
"Talk frequently with your health care provider, and request guidelines for adjusting your insulin dose until you achieve blood glucose control," says William Polonsky, Ph.D., CDE. Don’t wait three to six months between appointments to have your providers help you with adjusting your insulin dose(s). Eventually, you may need a more complex regimen that more closely mimics the way your pancreas releases insulin.
10 Guidelines for Starting Insulin
• Know your health care provider's plan up front. Ask what A1C and blood glucose measures are used and how you will start taking insulin.
• Think short-term, not long-term. Start taking insulin when your health care provider recommends it, and notice if you feel better and have more energy. Don’t try to put it off from appointment to appointment.
• Ask to be referred to a diabetes education program to learn the ins and outs of taking insulin and get the support you need.
• Have a plan with your health care provider to be in touch regularly to increase your dose until you hit your blood glucose targets.
• Get the inside scoop from people who have successfully transitioned to insulin. Try attending a support group or connecting with people willing to support you in one or more of the diabetes online communities.
• Explore your options for insulin delivery -- using the traditional vial and syringe, or using the more contemporary and convenient pens or possibly an insulin pump. Check your health insurance plan to see what it covers.
• Continue to eat well and exercise regularly.
• Strive for consistency. Take your insulin and eat at similar times every day when possible.
• Store insulin properly. Keep the pen or vial of insulin at room temperature (as long as you’ll use it up within 30 days), and store extras in the refrigerator.
• Carry a source of carbohydrate to treat low blood sugar, such as glucose tablets or hard candy. Start by using 15 grams of carbohydrate.
What About Your Pills?
Should you/will you stay on your diabetes pills when you start taking insulin?
Experts and health care providers have varying opinions. Many agree that you should stay on the pills that treat insulin resistance, such as metformin. Some health care providers suggest you stop taking pills that help your pancreas produce more insulin, such as sulfonylureas or meglitinides, while others don't. If you don't see improvement in blood sugar control, ask your health care provider questions and talk about options.
Types of Insulin
Insulin has come a long way. Today's insulin is more effective with less risk of hypoglycemia. There are now four main types of insulin -- some bolus, some basal.
Bolus insulin covers blood glucose rise from food.
Basal insulin covers between-meal and overnight blood glucose levels.
People generally need half of their insulin as bolus and half as basal.
The types of insulin differ in their action curve:
1. The onset: when insulin starts to lower blood glucose
2. The peak: when it lowers blood glucose the most
3. The duration: how long the effect lasts
The four main types of insulin are:
1. Rapid-acting: This bolus insulin starts to work about 15-20 minutes after it is taken (it can take longer depending on your body’s level of insulin resistance), helping to control glucose levels during and just after meals. Common names are lispro (Humalog), aspart (NovoLog), and glulisine (Apidra).
2. Short-acting or regular (R): This bolus insulin takes longer to lower blood glucose than rapid-acting insulin. It was the only bolus insulin prior to 1995 and is used much less now. Common examples are Humulin R and Novolin R.
3. Intermediate-acting (NPH): This insulin works slower and lowers blood glucose levels throughout the day to cover both basal and bolus needs. Common examples are Humulin N and Novolin N. Because there are now long-acting insulins, these insulins are used less frequently.
4. Long-acting: Glargine (Lantus) was introduced in 2001. Detemir (Levemir), introduced in 2005, was the second insulin in this basal category to be approved by the U.S. Food and Drug Administration. Both are taken once or twice a day.
In addition, several combination insulins are available with varying amounts of bolus and basal insulin to control blood sugar and make taking insulin simpler. People typically take one dose before breakfast and another before dinner.
How you take insulin is your choice. Your grandmother's shots with glass syringes and big needles are long gone. Now plastic syringes, fine needles, and other devices make taking insulin much easier. If you choose the traditional vial and syringe, work with your health care provider to pick the size of syringe and needle that are right for you. To make good use of the insulin you inject, you'll want the shortest needle and thinnest gauge.
Insulin pens come with single and combination insulins. You place a thin, short needle on the pen for each injection. To select a dose, you turn a dial and then press a plunger to deliver the insulin. Pens are convenient to carry and provide accurate dosing.
Insulin pumps typically use rapid-acting insulin. This insulin is delivered under the skin (the same as injections) continuously via a cannula (very thin tube) to meet both basal insulin needs and bolus needs. More people with type 2 diabetes are going on an insulin pump.
Talk to your health care provider, diabetes educator, or pharmacist about your options.
The Future of Insulin
More insulin advances are percolating. There will be new insulins that act even faster. Improvements will be made in the open-loop pumps currently on the market, and efforts continue to develop the so-called artificial pancreas, or closed-loop system that promises, with several different models, to control blood sugar without the person having to do all the thinking.
Work also progresses on alternate ways to take insulin. The second generation of inhaled insulin is on the way with the FDA’s approval of Afrezza in 2014. Investigation is ongoing for delivering insulin buccally -- via the tongue, throat, and cheeks -- or through a skin patch.
While the progress on new insulin products and delivery systems is encouraging, don't delay starting insulin if your health care provider and your diabetes health status indicate you need it now. The insulin available today is safe and relatively easy to take, and injections are nearly painless. Plus, starting to take insulin sooner rather than later may improve your health quickly and make your life better for many years to come.
More Insulin Resources
When you're faced with starting insulin, you may feel overwhelmed. To answer your questions and calm your fears, talk to your health care providers and use these resources:
Hope S. Warshaw, R.D., CDE, is a dietitian, diabetes educator, and author of the American Diabetes Association books Diabetes Meal Planning Made Easy and Guide to Healthy Restaurant Eating.