The Decision Not to Drive During Hypoglycemia in Patients With Type 1 and Type 2 Diabetes According to Hypoglycemia Awareness

  1. Alexander D.M. Stork, MD1,
  2. Timon W. van Haeften, MD1 and
  3. Thiemo F. Veneman, MD2
  1. 1Department of Internal Medicine and Metabolic Diseases, University Medical Center Utrecht, Utrecht, the Netherlands
  2. 2Department of Internal Medicine, Hospital Group Twente, Twenteborg, Almelo, the Netherlands
  1. Address correspondence and reprint requests to Alexander D.M. Stork, MD, Ds. Th. Fliednerstraat 1, 5631 BM Eindhoven, Netherlands. E-mail: adm.stork{at}


OBJECTIVE—In recent years, there has been an ongoing discussion on the relationship between diabetes and driving. As driving performance will inevitably decline at lower levels of glycemia, patients’ decisions concerning driving or taking corrective action when hypoglycemia occurs immediately before or during driving seems paramount.

RESEARCH DESIGN AND METHODS—Twenty-four type 1 diabetic patients with normal awareness of hypoglycemia (T1Norm group), 21 type 1 diabetic patients with impaired awareness of hypoglycemia (T1Imp group), and 20 type 2 diabetic patients with normal awareness of hypoglycemia (T2 group) were studied. They were asked whether they felt hypoglycemic and whether they would currently drive during experimental euglycemia (5.0 mmol/l) and hypoglycemia (2.7 mmol/l).

RESULTS—In the T1Norm group, 1 patient (4.2%) decided to drive during hypoglycemia. In the T1Imp group, 9 patients (42.9%) said they would drive in the hypoglycemic condition. In the T2 group, 5 patients (25%) would drive. This was more frequently the case for patients on oral hypoglycemic agents (χ2 = 4.44; P = 0.04). No effect of sex (χ2 = 0.78; P = 0.38) or age (χ2 = 0.22; P = 0.64) was noted.

CONCLUSIONS—Patients with type 1 diabetes and impaired awareness of hypoglycemia frequently decided to drive while hypoglycemic, whereas patients with type 1 diabetes and normal awareness of hypoglycemia appeared to make safe decisions concerning hypoglycemia and driving. Strikingly, patients with type 2 diabetes and normal hypoglycemia awareness frequently made potentially dangerous decisions as well, particularly when using oral hypoglycemic agents. Therefore, early, clear, and consistent education is imperative.


  • Published ahead of print at on 8 August 2007. DOI: 10.2337/dc06-1544.

    A.D.M.S. is currently affiliated with the Department of Internal Medicine, Máxima Medical Centre, Eindhoven, the Netherlands.

    A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C Section 1734 solely to indicate this fact.

    • Accepted August 1, 2007.
    • Received July 22, 2006.
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  1. Diabetes Care vol. 30 no. 11 2822-2826
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