Prediabetic states

Pre-diabetic states are metabolic conditions  that share features with diabetes but do not meet the diagnostic criteria

  • There are two main conditions to consider:
    • Impaired fasting glucose (IFG)
    • Impaired Glucose Tolerance (IGT)
Definitions

These definitions are based on NICE criteria (up to date as of Nov 2018) which are in turn based on WHO criteria

  • Normal is defined as
    1. Fasting glucose ≤6.0 mmol/l
    2. Postprandial/Random glucose ≤7.8 mmol/l
  • Diabetes is defined with either:
    1. Fasting glucose ≥7 mmol/l
    2. Postprandial/random glucose >11 mmol/l
    • Anything meeting these is therefore diabetes by definition
  • Impaired fasting glucose (IFG) – there is an impaired level of glucose when fasting (but tolerance to glucose intake is normal)
    • This is defined as:
      1. Fasting glucose from 6.1- 6.9 mmol/l
      2. Normal postprandial glucose (<7.8)
  • Impaired Glucose Tolerance (IGT) – there is an impaired tolerance to glucose intake (but fasting glucose is normal)
    • This is defined as:
      1. Normal Fasting glucose (I.e. <6 mmol/L )
      2. Abnormal 2 hour glucose = 7.8 – 11.0 mmol/l
        • Would be considered diabetic if >11

Summary

There are several possible outcomes based on the combination of glucose levels

  1. Both ≤6.0 and <7.8 = Normal
  2. 6.1-6.9 ±  7.8-11.0 =  IFG ± IGT
    • NB due to the values a patient can have both IGT/IFG without having Diabetes
  3. Either ≥7.0 or ≥11.1 = Diabetes
  • IFG and IGT are independent risk factors for diabetes development
    • Highlight different aspects of glucose metabolism abnormalities – i.e. fasting and post-prandial dysfunction respectively
    • IGT has a higher risk of progression
  • Both require annual review with lifestyle advice
    • In practice both are managed as diabetes