INTRODUCTION — Type 2 diabetes mellitus occurs when the pancreas (an organ in the abdomen) produces insufficient amounts of the hormone insulin and/or the body's tissues become resistant to normal or even high levels of insulin. This causes high blood glucose (sugar) 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 glucose levels. Treatment includes lifestyle adjustments, self-care measures, and medications, which can minimize the risk of diabetes and cardiovascular (heart-related) complications.
This topic review will discuss the treatment of type 2 diabetes. Separate topic reviews about other aspects of type 2 diabetes are also available. (See "Patient information: Diabetes mellitus; type 2" and see "Patient information: Self-blood glucose monitoring" and see "Patient information: Hypoglycemia (low blood glucose) in diabetes" and see "Patient information: Lifestyle modifications in type 2 diabetes" and see "Patient information: Preventing complications in diabetes mellitus").
TREATMENT GOALS
Blood glucose control — The goal of treatment in type 2 diabetes is to keep blood glucose levels at normal or near-normal levels. Careful control of blood glucose levels can help prevent the long-term effects of poorly controlled blood glucose (diabetic complications of the eye, kidney, and cardiovascular system).
Blood glucose control can be measured by checking the blood glucose level before the first meal of the day (fasting). A normal fasting blood glucose level is less than 100 mg/dL (5.6 mmol/L), although some people will have a different goal. A healthcare provider can help to determine this goal with the patient. Some people will need to test their blood glucose level before and/or after other meals during the day, and the frequency of testing can change as diabetes progresses. (See "Patient information: Self-blood glucose monitoring").
Blood glucose control can also be measured with a blood test called A1C. The A1C blood test measures the average blood glucose level during the past two to three months. The test is done by giving a small sample of blood from a vein or fingertip in a clinician's office. The goal A1C for most people with type 2 diabetes is 7.0 percent or less, which corresponds to an average blood glucose of 150 mg/dL (8.3 mmol/L, show figure 1). A healthcare provider can determine the A1C goal for an individual patient.
The average blood glucose goal (150 mg/dl or 8.3 mmol/L) is higher than the fasting blood glucose goal (100 mg/dL or 5.6 mmol/L) for several reasons. Blood glucose levels increase after eating. The amount and speed of the increase depend upon the type and amount of food eaten at a particular meal. The increase also depends upon the type and dose of diabetes treatment(s) used and the person's activity level.
Cardiovascular risk control — The most common long-term complication of type 2 diabetes is cardiovascular (heart) disease, which can cause myocardial infarction (heart attack), angina (chest pain), stroke, and even death. The risk of heart disease is estimated to be at least twice that of persons without diabetes. (See "Patient information: Preventing complications in diabetes mellitus").
However, persons with type 2 diabetes can substantially lower the risk of cardiovascular disease by quitting smoking, taking a low-dose aspirin every day, and by managing high blood pressure and hyperlipidemia (high cholesterol) with diet, exercise, and medications. (See "Patient information: High cholesterol and lipids (hyperlipidemia)" and see "Patient information: High blood pressure treatment" and see "Patient information: Smoking cessation" and see "Patient information: Aspirin and heart disease").
Persons with type 2 diabetes are also at increased risk of developing eye, kidney, and nerve complications that can result in blindness, kidney failure, foot ulcers requiring amputation, and impotence in men. These complications can occur after many years of diabetes and are related to elevated levels of blood glucose over time. Complications can be prevented or delayed by keeping blood sugar levels as close to normal as possible and by carefully controlling blood pressure. Diabetes remains the greatest cause of blindness, kidney failure, and amputations in the United States and in much of the world.
DIET — Changes in diet can improve many aspects of type 2 diabetes, including obesity, high blood pressure, and the body's ability to produce and respond to insulin. Response to dietary changes depends upon the number of calories consumed, types of foods chosen, and the amount of weight lost.
For a person who is newly diagnosed with diabetes and who is overweight or obese, losing any amount of weight can reduce or eliminate the need for medications and improve blood glucose levels.
The American Diabetes Association recommends a low fat, low calorie, high complex carbohydrate diet. A dietitian can help to determine the optimal number of calories and fat for an individual patient. (See "Patient information: Weight loss treatments").
The following are general diet recommendations: Eat a lot of vegetables and fruits, at least five servings a day. Limit starchy vegetables (eg, potatoes) but eat as many non-starchy fruits or vegetables as desired. Choose foods with whole grains rather than processed grains. Consider whole wheat bread, brown rice, or whole wheat pasta instead of white bread, white rice, or regular pasta. High fiber foods can help a person to feel fuller sooner; 15 to 30 grams of fiber are recommended daily (show table 1A-1C). Eat a limited amount of red meat, and choose lean cuts of meat that end in loin (pork loin, tenderloin, sirloin). Remove skin from chicken and turkey before eating. Include fish two to three times per week. Choose low or fat-free dairy products, such as skim milk, non-fat yogurt, and low-fat cheese. Avoid high calorie snack foods, including regular soda, fruit punch, candy, chips, cookies, cakes, and full-fat ice cream. Use liquid oils (olive, canola) instead of solid fats (butter, margarine, shortening) for cooking. Fat should be limited to less than 30 percent of a person's total daily calories. For a 1500 calorie per day diet, this would mean about 45 g or less of fat per day, which can be counted using the nutrition information labels on most food packages (show figure 2).
For patients who are not able to lose weight with diet alone, a weight loss medication may be considered. Patients with type 2 diabetes who have a BMI greater than 35 kg/m2 can also consider a surgical weight loss procedure. (See "Patient information: Weight loss treatments", section on Weight loss medications and see "Patient information: Weight loss surgery").
EXERCISE — Regular exercise can benefit people with type 2 diabetes, even if weight is not lost. Exercise improves blood glucose control because it improves the body's response to insulin. (See "Patient information: Exercise").
Exercise does not need to be vigorous and it does not need to be continuous to produce health benefits; it can be broken up into three or four ten-minute sessions per day. The recommended goal is 30 minutes of moderate-intensity exercise at least five days per week. However, exercising only one or two days per week is better than not exercising at all.
PSYCHOLOGICAL TREATMENTS — Patients with type 2 diabetes often experience significant stress related to their disease and the increased responsibilities that come with it, including blood glucose testing, dietary considerations, exercise, healthcare provider visits, the need for medication, 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 oneself 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 clinicians can help patients to understand their diagnosis and the need for treatment.
Involving family and friends can help people with diabetes to manage their disease by offering reminders to take medication, test blood glucose 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 patients with type 2 diabetes to cope with new responsibilities and worries. A number of studies have shown that patients who have psychotherapy in addition to traditional medical care have reduced stress and improved blood glucose control compared to patients who received only traditional care [1].
MEDICATION — A number of oral medications are available for the treatment of type 2 diabetes. A table of these medications is available in table 2 (show table 2).
Metformin — Most patients who are newly diagnosed with type 2 diabetes will immediately begin a medication called metformin (Glucophage®, Gumetza®, Riomet®, Fortamet®). Metformin improves the body's response to insulin to reduce elevated blood glucose levels.
Metformin is a pill that is usually started with a dose of 500 mg with the evening meal; a second dose may be added one to two weeks later (500 mg with breakfast). The dose may be increased every one to two weeks thereafter, up to a total of 850 mg twice per day.
Common side effects of metformin include nausea, diarrhea, and gas. These are usually not severe, especially if metformin is taken along with food and the dose is increased gradually. Patients with certain types of kidney, liver, and heart disease, and those who drink alcohol excessively should not take metformin. It should not be taken within 48 hours of any test that uses iodine-based contrast dye, and it should be stopped before surgical procedures. It is not recommended for patients older than 80 years unless kidney function testing shows that the kidneys are functioning well.
When to add a second medication — For patients who initially take metformin, a second medication may be added within the first two to three months if blood glucose control is not adequate. "Adequate" control is defined as an A1C level less than 7 percent for most people; insulin may be recommended if the A1C is elevated, especially if it is higher than 8.5 percent.
Sulfonylureas — Sulfonylureas have been used to treat type 2 diabetes for many years. They work by increasing insulin production, and can lower blood glucose levels by approximately 20 percent. However, they lose effectiveness over time. Sulfonylureas are generally used if metformin does not adequately control blood glucose levels when taken alone, but may be used first in people who have liver, kidney, or heart disease and in those who drink alcohol excessively. They should not be used by patients who 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; their efficacy is similar. The medication is in pill form and is taken once or twice daily.
Patients who take sulfonylureas are at risk of low blood glucose, known as hypoglycemia. This can cause sweating, shaking, hunger, and anxiety, and must be treated quickly by eating 10 to 15 grams of fast-acting carbohydrate (eg, fruit juice, hard candy, glucose tablets). Delaying treatment can cause the person to lose consciousness. A full discussion of hypoglycemia is available separately. (See "Patient information: Hypoglycemia (low blood glucose) in diabetes").
Insulin — In the past, insulin treatment was reserved for patients with type 2 diabetes who did not have adequate blood glucose control with oral medications 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 patients, or it can be added to or substituted for oral medications.
Insulin requires an injection by the patient or a family member/friend. Inhaled insulin is newly available, but its effectiveness in treating type 2 diabetes is still being evaluated.
Most patients with type 2 diabetes begin by taking one insulin injection per day, usually at 10 P.M. The dose can be slowly increased every few days, depending upon the person's first morning blood glucose level (which should be measured every morning before eating). Some patients will need additional injections throughout the day while others have a good response to only one injection per day.
Meglitinides — Meglitinides include repaglinide (Prandin®) and nateglinide (Starlix®). They work to lower blood glucose levels, similar to the sulfonylureas, and may be used in patients who are allergic to sulfa-based drugs. They are taken in pill form. These medications 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.
Thiazolidinediones — This class of medications includes rosiglitazone (Avandia®) and pioglitazone (Actos®), which work to lower blood glucose levels by increasing the body's sensitivity to insulin. They are taken in pill form and usually used second-line, in combination with other medications such as metformin, a sulfonylurea, or insulin.
Common side effects of thiazolidinediones include weight gain and swelling of the feet and ankles. There is a small but serious risk of developing or worsening congestive heart failure in patients who use thiazolidinediones. Close monitoring of swelling is important to detect this condition.
Alpha-glucosidase inhibitors — These medications, which include acarbose (Precose®) and miglitol (Glyset®), work by interfering with the absorption of carbohydrates in the intestines. This results in lower blood glucose levels, though are not as effective as metformin or the sulfonylureas. They can be combined with other medications if the first medication does not lower blood glucose levels sufficiently.
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 medication is usually taken three times per day with the first bite of each meal.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Institute of Diabetes and Digestive and Kidney Diseases
(www.niddk.nih.gov/)
American Diabetes Association (ADA)
(800)-DIABETES (800-342-2383)
(www.diabetes.org)
Canadian Diabetes Associates
(www.diabetes.ca)
U.S. Center for Disease Control and Prevention
(www.cdc.gov/diabetes)
[1-4]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Ismail, K, Winkley, K, Rabe-Hesketh, S. Systematic review and meta-analysis of randomised controlled trials of psychological interventions to improve glycaemic control in patients with type 2 diabetes. Lancet 2004; 363:1589.
2. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group. Lancet 1998; 352:837.
3. Nathan, DM, Buse, JB, Davidson, MB, et al. Management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes. Diabetes Care 2006; 29:1963.
4. Norris, SL, Zhang, X, Avenell, A, et al. Long-term effectiveness of lifestyle and behavioral weight loss interventions in adults with type 2 diabetes: a meta-analysis. Am J Med 2004; 117:762.
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