Some people with diabetes need to be extra cautious before getting behind the wheel

Driving Image

Most people think of inebriation, visual impairment, inexperience and aging as factors that increase the risk of having an accident while driving. One factor you may not think of is diabetes.

If you didn't think of it, you're not alone. Many people, including a substantial number of individuals with diabetes, aren't aware of the potential risks. In fact, a large international study found that nearly 50 percent of drivers with type 1 diabetes and 75 percent of those with type 2 diabetes have never had a discussion with their doctors about driving.

While this might not be a concern if you're not at increased risk of having a collision, it's certainly a conversation to have if you are. How do you know where you stand?

Recently, the American Diabetes Association (ADA) issued a position statement that helps identify who's at increased risk—most people with diabetes are not—and it offers advice on important precautions that can help keep you safe when you're operating a motor vehicle.

Determining risk

It's important to reiterate that diabetes in and of itself is not a risk factor for driving accidents. If you're like most people with diabetes, you can, in fact, safely operate a motor vehicle without creating any meaningful risk of injury to yourself or others. That may not be the case, however, if you have recently experienced severe hypoglycemia (defined as a blood glucose level so low that it disrupts your ability to function, causing you to need help from someone else to administer carbohydrates or glucagon or take resuscitative action).

According to the ADA, a history of severe hypoglycemia in the past year or two is the single most significant factor associated with driving collisions for drivers with diabetes, regardless of the type of diabetes or the treatment used. Findings from a 2009 study of nearly 500 drivers with type 1 diabetes demonstrated that people who had two episodes of severe hypoglycemia in the preceding year were 12 percent more likely to have a collision than their counterparts who had not experienced such an episode. In addition, individuals who had two collisions in the previous two years had a 40 percent increased risk of having another collision.

The study focused on people with type 1 diabetes because they are more likely than individuals with type 2 diabetes to be affected by severe hypoglycemia. However, not all people with type 1 diabetes are prone to seriously low blood glucose levels.

The ADA estimates that about 80 percent of episodes of severe hypoglycemia affect approximately 20 percent of people with type 1 diabetes. In addition, evidence suggests that a small subgroup of drivers with type 1 diabetes account for the majority of hypoglycemia-related collisions.

Moderate hypoglycemia is a concern as well. Several studies have demonstrated that it has a significant and consistent adverse effect on driving safety. This most likely occurs because moderate hypoglycemia impairs cognition, potentially affecting judgment about whether it's safe to continue to drive under the circumstances without consuming a carbohydrate to boost glucose levels.

Publication Review By: Rita Rastogi Kalyani, M.D., and Simeon Margolis, M.D., Ph.D.

Published: 05 May 2013

Last Modified: 11 Sep 2015