Medical Conditions and Driving: A Review of the Literature (1960 – 2000)
TRD Page
Foreword
Acknowledgements
Section1: Introduction
Section 2: Vision
Section 3: Hearing
Section 4: Cardiovascular
Section 5: Cerebrovascular
Section 6: Peripheral Vascular
Section 7: Nervous System
Section 8: Respiratory
Section 9: Metabolic
Section 10: Renal
Section 11: Musculoskeletal
Section 12: Psychiatric
Section 13: Drugs
Section 14: Aging Driver
Section 15: Anesthesia and Surgery
Appendix A
List of Tables
List of Figures
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Section 9: Metabolic Diseases

Predictors of Hypoglycemia Unawareness

A number of studies have examined factors that may be associated with hypoglycemic unawareness. A summary of the literature is provided in Table 28. As can be seen, factors that may be associated with hypoglycemic unawareness include age, duration of diabetes, presence or absence of autonomic neuropathy, species of insulin, degree of metabolic control, and hypoglycemia itself. To date, most studies that have examined hypoglycemic unawareness in individuals with diabetes have relied on questionnaires to classify subjects, a methodology which may limit the findings. Gerich et al. (1991) suggest that in future investigations, subjects should be categorized on the basis of prospectively obtained objective criteria such as glycemic thresholds for development of autonomic symptoms obtained during a standardized insulin infusion test.

Although a number of factors have been proposed to be associated with hypoglycemia unawareness, there is a paucity of literature addressing this issue. More research is needed before any definitive statements can be made regarding risk factors for hypoglycemia unawareness. Nevertheless, hypoglycemia unawareness is a major risk factor for the development of severe hypoglycemia and therefore should be a major concern for individuals with diabetes who drive.

Table 28  Summary of Studies Examining Possible Predictors of Hypoglycemia

Factor

Study

Age

Hepburn et al. (1990)

Duration of Diabetes

Hepburn et al. (1990)
Mokan et al. (1994)
Ward et al. (1990)

Autonomic Neuropathy

Cryer & Gerich (1983)
Heller et al. (1987)
Hoeldtke et al. (1982)
Sussman et al. (1963)

Species of Insulin

↑ Risk:
Teuscher & Berger (1987)

No Difference:
Egger et al. (1991)
Gale & Tattersal (1979)
Jones et al. (1991)
Muhlhasser et al. (1991)
Orchard et al. (1991)
Schwarz et al. (1990)

Increased Metabolic Control

Mokan et al. (1994)

Hypoglycemia itself

Banting et al. (1923)
Goldfein et al. (1961)
Heller & Cryer (1991)
Joslin et al. (1924)
Maddock & Trimble (1928)
Widom & Simonson (1990)

 

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