Type 1 Diabetes Driving Mishaps Common
Type 1 Patients Have Twice as Many Accidents, Violations as Type 2 Patients and Non-Diabetics
Aug. 20, 2003 -- Driving accidents and traffic violations are twice as common among people with type 1 diabetes as in people with type 2 diabetes or those without the disease, suggests a new study that explains why: One in three people with type 1 diabetes surveyed say they had experienced at least one hypoglycemic stupor in a two-year period.
Hypoglycemia results when blood sugar levels are abnormally low -- causing trembling, dizziness, confusion, belligerence, blurred vision, and sometimes unconsciousness. They can occur frequently in people with diabetes on insulin therapy, those attempting to achieve "tight" (near) normal glucose control with intensive insulin therapy, and in people with diabetes that have numerous complications from the disease. By comparison, episodes of hypoglycemia were reported by only 8% of people with type 2 diabetes.
Though hypoglycemia is generally more likely to occur in any person with diabetes who requires insulin, researchers found no difference in traffic mishaps between people with type 2 diabetes who use insulin and those who did not. In fact, patients with type 2 diabetes had a similar rate of accidents as people without diabetes -- and half their rate of traffic violations.
But the study's lead researcher says the real message of these findings, published in this month's issue of Diabetes Care, is that many doctors fail to warn patients who have diabetes about the potential dangers of driving with low blood sugar levels.
"Most of the patients in our study say their doctors never spoke to them about hypoglycemia driving, even though they are legally liable to do so," Daniel J. Cox, PhD, of the University of Virginia, tells WebMD. "There's one case where a patient had a hypoglycemic stupor, drove off the road, and had a head-on collision that killed a mother and her daughter in other car. That patient and the family of the victim then sued the physician because he knew the patient was having hypoglycemia but never counseled him that he shouldn't be driving under such conditions."
Cox, director of the university's Behavioral Medicine Center and a professor of psychiatric medicine who has done previous research on this topic, and his colleagues distributed anonymous questionnaires to 341 type 1 diabetic people, 322 type 2 diabetic people, and 363 non-diabetic spouses in the U.S. and Europe.
Sixteen percent of those with type 1 diabetes and 8% of those with type 2 diabetes surveyed in the U.S. reported car crashes in the two-year study period. Among European participants, the gap was closer -- accidents occurred among 23% of type 1 and 19% of type 2 patients.
Check Blood Sugar Before Driving
"My recommendation is that diabetics should never start driving when their blood glucose is below 90 mg/dL -- not because they are impaired at that level, but it wouldn't take them to drop much further to be impaired," he tells WebMD. "If it's below 70 mg/dL, they need to take some fast-acting carbohydrates before driving and not resume driving until their blood glucose recovers, which can take up to 30 minutes."