impaired glucose tolerance (IGT)

Last reviewed 07/2021

This is a stage of impaired glucose regulation (Fasting plasma glucose < 7.0 mmol/l and OGTT 2-hour value >= 7.8 mmol/l but < 11.1 mmol/l).

The risk of subsequent conversion to diabetes is about 4.7% per year in Caucasians and higher in some ethnic minority groups.

  • these people should be followed up annually to reassess glucose regulation and all other cardiovascular risk factors (2)

The incidence of impaired glucose tolerance is:

  • 17% of those aged 40-65 in the UK (3)
  • 11% of those aged 20-74 in the US (4)

Complications of impaired glucose tolerence include:

  • cardiovascular disease - in middle aged men with glucose intolerence have double the risk of death from cardiovascular disease (5)
  • study evidence has revealed an increased mortality risk associated with IGT (6)
    • impaired glucose tolerance was associated with an increased mortality risk (HR 1.5, 95% CI 1.1 to 2.0)