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.
“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).
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.