Anti-diabetic drug use and the risk of motor vehicle crash in the elderly

Can J Clin Pharmacol. Winter 2006;13(1):e112-20. Epub 2006 Mar 31.


Background: Studies of the risk of motor vehicle crash associated with diabetes have produced conflicting results.

Objectives: To assess whether the use of anti-diabetic drugs among the elderly increases the risk of motor vehicle crash.

Methods: The computerized databases of the various universal insurance programs of Québec were linked to form a cohort of all 224,734 elderly drivers that was followed from 1990-1993. Using a nested case-control approach, all 5,579 drivers involved in an injurious crash (cases) and a random sample of 13,300 control subjects were identified. Exposure to anti-diabetic drugs was assessed in the year preceding the index date, namely the date of the crash for the cases and a randomly selected date during follow-up for the controls.

Results: The adjusted rate ratio of an injurious crash was 1.4 (95% CI: 1.0-2.0) for current users of insulin monotherapy relative to non-users and 1.3 (95% CI: 1.0-1.7) for sulfonylurea and metformin combined. Monotherapy, using either a sulfonylurea or metformin, was not associated with an increased risk. There was a dose-response effect in subjects using high doses of combined oral therapy (RR 1.4; 95% CI: 1.0-2.0). For users of insulin monotherapy or of high doses of combined oral therapy, the increase corresponds to an excess rate of 32 crashes per 10,000 elderly drivers per year.

Conclusions: L Elderly drivers treated with insulin monotherapy or a combination of sulfonylurea and metformin, especially at high doses, have a small increased risk of injurious crashes. There is no increased risk associated with any regimen of oral monotherapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accidents, Traffic / statistics & numerical data*
  • Aged
  • Diabetes Mellitus / drug therapy
  • Female
  • Humans
  • Hypoglycemic Agents / adverse effects*
  • Hypoglycemic Agents / therapeutic use
  • Logistic Models
  • Male
  • Metformin / adverse effects*
  • Metformin / therapeutic use
  • Quebec / epidemiology
  • Sulfonylurea Compounds / adverse effects*
  • Sulfonylurea Compounds / therapeutic use


  • Hypoglycemic Agents
  • Sulfonylurea Compounds
  • Metformin