TYPE 2 DIABETES OVERVIEW
Type 2 diabetes mellitus occurs when the pancreas (an organ in the abdomen) produces insufficient amounts of the hormone insulin and/or the body becomes resistant to normal or even high levels of insulin. This causes high blood sugar (glucose) levels, which can lead to a number of complications if untreated.
People with type 2 diabetes require regular monitoring and ongoing treatment to maintain normal or near-normal blood sugar levels. Treatment includes lifestyle adjustments, self-care measures, and medicines, which can minimize the risk of diabetes and cardiovascular (heart-related) complications.
This topic review will discuss the treatment of type 2 diabetes. Topics that discuss other aspects of type 2 diabetes are also available. (See "Patient information: Diabetes mellitus type 2: Overview (Beyond the Basics)" and "Patient information: Diabetes mellitus type 2: Insulin treatment (Beyond the Basics)" and "Patient information: Type 2 diabetes mellitus and diet (Beyond the Basics)" and "Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)" and "Patient information: Hypoglycemia (low blood sugar) in diabetes mellitus (Beyond the Basics)" and "Patient information: Diabetes mellitus type 2: Alcohol, exercise, and medical care (Beyond the Basics)" and "Patient information: Preventing complications in diabetes mellitus (Beyond the Basics)".)
TYPE 2 DIABETES TREATMENT GOALS
Blood sugar control — The goal of treatment in type 2 diabetes is to keep blood sugar levels at normal or near-normal levels. Careful control of blood sugars can help prevent the long-term effects of poorly controlled blood sugar (diabetic complications of the eye, kidney, and cardiovascular system).
Home blood sugar testing — In people with type 2 diabetes, home blood sugar testing might be recommended, especially in those who take oral diabetes medicines or insulin shots. Home blood sugar testing is not usually necessary for people who are diet-controlled. (See "Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)".)
A normal fasting blood sugar is less than 100 mg/dL (5.6 mmol/L), although some people will have a different goal. Your doctor or nurse can help set your blood sugar goal.
A1C testing — Blood sugar control can also be estimated with a blood test called A1C. The A1C blood test measures your average blood sugar level during the past two to three months. The goal A1C for most people with type 2 diabetes is 7 percent or less, which corresponds to an average blood sugar of 150 mg/dL (8.3 mmol/L) (table 1). For some people a higher HbA1c goal than this is safer and leads to better health outcomes. A healthcare provider can help determine your A1C goal.
Your average blood sugar (150 mg/dL or 8.3 mmol/L) is higher than your fasting blood sugar goal (100 mg/dL or 5.6 mmol/L) for several reasons:
- Blood sugar goes up after eating.
- How much and how fast your blood sugar goes up depends on the type and amount of food you eat at a particular meal.
- The amount your blood sugar goes up also depends on what diabetes treatment(s) you use and your activity level.
Cardiovascular risk control — The most common long-term complication of type 2 diabetes is cardiovascular (heart) disease, which can lead to heart attack, chest pain, stroke, and even death. People with type 2 diabetes have twice the risk of heart disease as those without diabetes.
However, you can substantially lower your risk of cardiovascular disease by:
- Quitting smoking
- Managing high blood pressure and high cholesterol with diet, exercise, and medicines
- Taking a low-dose aspirin (81 mg) every day, if indicated
A detailed discussion of ways to prevent complications is available separately. (See "Patient information: Preventing complications in diabetes mellitus (Beyond the Basics)".)
DIET AND EXERCISE IN TYPE 2 DIABETES
Changes in diet can improve many aspects of type 2 diabetes, including your weight, blood pressure, and your body's ability to produce and respond to insulin. Detailed information about type 2 diabetes and diet is available separately. (See "Patient information: Type 2 diabetes mellitus and diet (Beyond the Basics)".)
Regular exercise can help control type 2 diabetes, even if you do not lose weight. Exercise improves blood sugar control because it improves how your body responds to insulin. (See "Patient information: Diabetes mellitus type 2: Alcohol, exercise, and medical care (Beyond the Basics)".)
TYPE 2 DIABETES MEDICINES
A number of oral medicines (pills) are available to treat type 2 diabetes.
Metformin — Most people who are newly diagnosed with type 2 diabetes will immediately begin a medicine called metformin (Glucophage®, Gumetza®, Riomet®, Fortamet®). Metformin improves how your body responds to insulin to reduce high blood sugar levels.
Metformin is a pill that is usually started with the evening meal; a second dose may be added one to two weeks later (with breakfast). The dose may be increased every one to two weeks thereafter.
Side effects — Common side effects of metformin include nausea, diarrhea, and gas. These are usually not severe, especially if you take metformin along with food.
Patients with certain types of kidney, liver, and heart disease, and those who drink alcohol excessively should not take metformin. You should stop taking metformin 48 hours before any test that uses iodine-based contrast dye (like a CT scan with contrast), and you should stop it before any type of surgery.
When to add a second medicine — Your doctor or nurse might recommend a second medicine within the first two to three months if your blood sugar levels are still higher than your goal. Insulin shots might be recommended if your A1C is higher than 8.5 percent. (See "Patient information: Diabetes mellitus type 2: Insulin treatment (Beyond the Basics)".)
Which second medicine is best? — If your blood sugar levels are still high after two to three months, but your A1C is close to the goal (between 7 and 8.5 percent), a second medicine might be added. The "best" second medicine depends upon individual factors, including the person's weight, other medical problems, and preferences regarding use of injections. The following are general recommendations:
- The most commonly recommended second medicine is a short acting sulfonylurea, such as glipizide (see 'Sulfonylureas' below).
- A thiazolidinedione, such as pioglitazone, is an alternative to sulfonylureas, but only for people who are not at increased risk of heart failure or bone fracture (see 'Thiazolidinediones' below).
- A GLP-agonist, such as exenatide, is an option for patients who are overweight and who want to avoid developing low blood sugar. (See 'GLP-agonists' below.)
- A meglitinide, such as repaglinide, is an option for people who cannot take a sulfonylurea or prefer to avoid injections. (See 'Meglitinides' below.)
Sulfonylureas — Sulfonylureas have been used to treat type 2 diabetes for many years. They work by increasing the amount of insulin your body makes, and can lower blood sugar levels by approximately 20 percent. However, they stop working over time.
Sulfonylureas are generally used if metformin does not adequately control blood sugar levels when taken alone. You should not take a sulfonylurea if you are allergic to sulfa drugs.
A number of sulfonylureas are available (Diabinese®, Orinase®, Glucotrol®, Diabeta®, Micronase®, Glynase®, Amaryl®), and the choice between them depends mainly upon cost and availability; they work similarly.
If you take a sulfonylurea, you can develop low blood sugar, known as hypoglycemia. Low blood sugar symptoms can include:
- Feeling hungry
- Feeling anxious
Low blood sugar must be treated quickly by eating 10 to 15 grams of fast-acting carbohydrate (eg, fruit juice, hard candy, glucose tablets). It is possible to pass out if you do not treat low blood sugar fast enough. A full discussion of low blood sugar is available separately. (See "Patient information: Hypoglycemia (low blood sugar) in diabetes mellitus (Beyond the Basics)".)
Insulin — In the past, insulin treatment was reserved for patients with type 2 diabetes whose blood sugars were not controlled with oral medicines and lifestyle changes. However, there is increasing evidence that using insulin at earlier stages may improve overall diabetes control and help to preserve the pancreas's ability to make insulin.
Insulin injections may be used as a first-line treatment in some people with type 2 diabetes, or it can be added to or substituted for oral medicines. Insulin must be injected by the patient or a family member/friend. (See "Patient information: Diabetes mellitus type 2: Insulin treatment (Beyond the Basics)".)
Thiazolidinediones — This class of medicines includes pioglitazone (Actos®), which work to lower blood sugar levels by increasing the body's sensitivity to insulin. They are taken in pill form and usually in combination with other medicines such as metformin, a sulfonylurea, or insulin.
Common side effects of thiazolidinediones include:
- Weight gain and swelling of the feet and ankles.
- A small but serious increased risk of developing or worsening heart failure. An early sign of heart failure is swelling of the feet and ankles. People who take thiazolidinediones should monitor for swelling.
- A small but serious increased risk of developing fluid retention at the back of the eyes (macular edema).
- A small but serious increased risk of developing certain types of cancer (like bladder cancer).
- A small increased risk of bone fractures.
GLP-agonists — The GLP-agonists, Exenatide (Byetta®) and liraglutide (Victoza), are injectable medicines. They are not a first-line treatment, but might be considered for people whose blood sugar is not controlled on the highest dose of one or two oral medicines. They may be especially helpful for overweight patients who are gaining weight on oral medicine.
GLP-agonists do not usually cause low blood sugar. They promote weight loss, but can also cause bothersome side-effects, including nausea, vomiting, and diarrhea. Pancreatitis has been reported rarely in patients taking GLP-agonists, but it is not known if the drugs caused the pancreatitis. You should stop taking exenatide or liraglutide if you develop severe abdominal pain. Exenatide should not be used in patients with abnormal kidney function. These drugs are more expensive than insulin. Because they are relatively new drugs, long-term risks and benefits are not known.
DPP-IV Inhibitors — This class of medicines includes sitagliptin (Januvia), saxagliptin (Onglyza), linagliptin (Tradjenta), and vildagliptin (Galvus). Vildagliptin is available in Europe but not in the United States. They lower blood sugar levels by increasing insulin release from the pancreas in response to a meal. They are not a first-line treatment, but they can be given alone in patients who can’t tolerate the first-line medicines (metformin, sulfonylureas), or they can be given with other oral medicines if blood sugars are still higher than goal. These medicines do not cause hypoglycemia or changes in body weight. However, they may cause some nausea and diarrhea. There have been rare reports of pancreatitis and skin reactions. DPP-IV inhibitors are expensive, and the long-term risks and benefits are unknown.
Meglitinides — Meglitinides include repaglinide (Prandin®) and nateglinide (Starlix®). They work to lower blood sugar levels, similar to the sulfonylureas, and might be recommended in people who are allergic to sulfa-based drugs. They are taken in pill form. Meglitinides are not generally used as a first-line treatment because they are more expensive than sulfonylureas and are short-acting, so they must be taken with each meal.
Alpha-glucosidase inhibitors — These medicines, which include acarbose (Precose®) and miglitol (Glyset®), work by interfering with the absorption of carbohydrates in the intestines. This helps to lower blood sugar levels, but not as well as metformin or the sulfonylureas. They can be combined with other medicines if the first medicine does not lower blood sugar levels enough.
The main side effects of alpha-glucosidase inhibitors are gas (flatulence), diarrhea, and abdominal pain; starting with a low dose may minimize these side effects. The medicine is usually taken three times per day with the first bite of each meal.
LIVING WITH TYPE 2 DIABETES
People with type 2 diabetes often feel stress related to their disease and the increased responsibilities that come with diabetes, including blood sugar testing, watching the diet, exercise, doctor visits, the need for medicines, and the potential risks of complications. It is not uncommon to become depressed as a result of this stress, and this can make taking care of yourself more difficult.
Committing to new treatments and lifestyle changes can be difficult, and it is not uncommon to feel that the benefits of treatment are not worth the effort. Having an open and honest discussion with a doctor or nurse can help you to understand your diagnosis and the need for treatment.
Involving family and friends can help you to manage your disease by offering reminders to take medicine, test blood sugar levels, and providing a ride to appointments. Family and friends can also give encouragement and support to eat a healthy diet and stick with an exercise plan.
Working with a psychotherapist or social worker can help you cope with new responsibilities and worries. A number of studies have shown that people who have psychotherapy in addition to traditional medical care have reduced stress and improved blood sugar control compared with people who received only traditional care .
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Treatment for type 2 diabetes (The Basics)
Patient information: Type 2 diabetes (The Basics)
Patient information: Using insulin (The Basics)
Patient information: Low blood sugar in people with diabetes (The Basics)
Patient information: Nonalcoholic steatohepatitis (NASH) (The Basics)
Patient information: Exercise (The Basics)
Patient information: Counting carbs if you do not use insulin (The Basics)
Patient information: Preventing type 2 diabetes (The Basics)
Patient information: Diabetic ketoacidosis (The Basics)
Patient information: Hyperosmolar nonketotic coma (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Diabetes mellitus type 2: Overview (Beyond the Basics)
Patient information: Diabetes mellitus type 2: Insulin treatment (Beyond the Basics)
Patient information: Type 2 diabetes mellitus and diet (Beyond the Basics)
Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)
Patient information: Hypoglycemia (low blood sugar) in diabetes mellitus (Beyond the Basics)
Patient information: Diabetes mellitus type 2: Alcohol, exercise, and medical care (Beyond the Basics)
Patient information: Preventing complications in diabetes mellitus (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Alpha-glucosidase inhibitors and lipase inhibitors for treatment of diabetes mellitus
Estimation of blood glucose control in diabetes mellitus
Glycemic control and vascular complications in type 2 diabetes mellitus
Insulin therapy in type 2 diabetes mellitus
Management of persistent hyperglycemia in type 2 diabetes mellitus
Metformin in the treatment of adults with type 2 diabetes mellitus
Overview of medical care in adults with diabetes mellitus
Sulfonylureas and meglitinides in the treatment of diabetes mellitus
Thiazolidinediones in the treatment of diabetes mellitus
The following organizations also provide reliable health information.
- National Library of Medicine
- American Diabetes Association (ADA)
- Canadian Diabetes Associates
- US Center for Disease Control and Prevention