When most people find out they have Type 2 diabetes, they are first instructed to make changes in their diet and lifestyle. These changes, which are likely to include routine exercise, more nutritious food choices, and often a lower calorie intake, are crucial to managing diabetes and may successfully lower blood glucose levels to an acceptable level. If they do not, a drug such as glyburide, glipizide, or metformin is often prescribed. But lifestyle changes and oral drugs for Type 2 diabetes are unlikely to be permanent solutions. This is because over time, the pancreas tends to produce less and less insulin until eventually it cannot meet the body’s needs. Ultimately, insulin (injected or infused) is the most effective treatment for Type 2 diabetes.
There are many barriers to starting insulin therapy: Often they are psychological; sometimes they are physical or financial. But if insulin is begun early enough and is used appropriately, people who use it have a marked decrease in complications related to diabetes such as retinopathy (a diabetic eye disease), nephropathy (diabetic kidney disease), and neuropathy (nerve damage). The need for insulin should not be viewed as a personal failure, but rather as a largely inevitable part of the treatment of Type 2 diabetes. This article offers some practical guidance on starting insulin for people with Type 2 diabetes.
When to start insulin
Insulin is usually started when oral medicines (usually no more than two) and lifestyle changes (which should be maintained for life even if oral pills or insulin are later prescribed) have failed to lower a person’s HbA1c level to less than 7%. (HbA1c stands for glycosylated hemoglobin and is a measure of blood glucose control.) However, a recent consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes suggested that insulin is a reasonable choice if a person’s HbA1c level remains above 7% while he is taking metformin alone. (The effects of metformin should be seen within three to four months of starting it.)
Large studies of people with Type 2 diabetes have shown that only about 30% of people taking two oral medicines have an HbA1c level of less than 7% after three years. Insulin is usually recommended as the initial therapy for diabetes if a person’s HbA1c level at diagnosis is greater than 10% or if someone’s fasting blood glucose level is consistently above 250 mg/dl.
Studies have shown that many doctors wait until someone’s HbA1c level is higher than 9% to start insulin therapy, which often results in months or years of high blood glucose and an increased risk of developing complications later on. One unfortunate reality is that many busy medical practices are not set up to address the needs of people who take insulin. Starting insulin requires education and easy access to health-care providers who are knowledgeable about insulin therapy, including diabetes nurse educators, pharmacists, and doctors.
Types of insulin
There have been significant innovations in insulin products over the last several years that have made insulin therapy more effective, more accessible, and safer. Before starting insulin, it is helpful to understand its function in the body. Insulin is needed for most cells throughout the body to take in glucose from the blood, which the cells use as fuel. In people without diabetes, the pancreas continuously secretes insulin at a background, or basal, level to provide a stable supply of glucose to the body’s cells and prevent a buildup of glucose in the blood as glucose is steadily released from the liver. In response to eating, the pancreas secretes a larger pulse, or bolus, of insulin. This bolus of insulin allows the liver to store energy from the food for later use instead of releasing it as glucose all at once, stabilizing the blood glucose level.