Choosing a treatment
Once a diagnosis is made, it’s time to decide on a form of treatment. The recommendations of professional medical bodies are a major source of guidance for doctors when prescribing treatment. Such recommendations are often based on multiple large studies that outline the benefits as well as the potential side effects of each of the potential therapies.
In the United States, treatment guidelines are issued by the National Institutes of Health (NIH), as well as by organizations such as the ADA. Guidelines issued by the NIH can be found online at the Web site of the National Guideline Clearinghouse, www.guideline.gov. They are usually written by experts with comments from outside reviewers as well as public comments prior to their publication. Guidelines written by professional societies are usually written by expert panels composed of members of that society.
Guidelines for the treatment of the various types of diabetes have been published by a number of organizations, including the ADA, the American Association of Clinical Endocrinologists (AACE), the European Association for the Study of Diabetes, the International Diabetes Federation, and others. Such guidelines include not just how the condition is to be treated but what the treatment should accomplish (the “goals” of treatment). However, not all of the organizations recommend the same treatment approach or agree on the goals of treatment. For example, the ADA suggests a goal of an HbA1c level lower than 7% for most adults with diabetes, while the AACE suggests a goal of less than 6.5%. This can lead to differences in the recommendations made by individual practitioners to their patients.
In people with Type 1 diabetes, the goal of treatment is to replace the body’s natural insulin with manufactured insulin so that blood glucose levels stay in a near-normal range. Doctors establish a starting dose, often based on body size, then make dose adjustments based on daily blood glucose monitoring and periodic HbA1c tests. In many cases, the person with Type 1 diabetes is educated to make daily dose adjustments independently.
In people with Type 2 diabetes, the goal is also to lower blood glucose levels to the near-normal range, but treatment may or may not include insulin. In general, changes in lifestyle are included in all Type 2 diabetes treatment recommendations. The drug metformin is usually considered to be the first drug of choice. The ADA then suggests the addition of insulin or a drug in the sulfonylurea class (such as glimepiride, glyburide, or glipizide). Long-acting insulin is often added to supplement oral drugs in people with Type 2 diabetes, although some studies suggest that adding rapid-acting insulin at mealtimes may be equally effective and could be done first. The ADA recommendations also allow for the use of other approved diabetes drugs in selected people.
The AACE’s recommended approach to treating Type 2 diabetes varies based on a person’s HbA1c at diagnosis. It also suggests using some newer drugs, such as those in the class known as DPP-4 inhibitors (such as Januvia) and those known as GLP-1 agonists (such as Byetta) at an earlier stage of treatment.
Both of these approaches to treatment are based on expert committee reviews of the scientific literature, and both encourage adding to or changing the drug regimen quickly — within one to three months — if the current one has not lowered HbA1c level to goal.
In addition to the recommendations of professional medical bodies, doctors also rely on their medical training, their previous experience treating the condition in question, and any continuing education they have received when prescribing treatment.