Diagnosis of Type 2 Diabetes & IGT Flashcards

1
Q

In what 2 ways can T2DM be diagnosed?

A
  • Plasma glucose (Once if symptomatic. Twice if asypmtomatic)
    • Fasting glucose >=7 mmol/l
    • Random glucose or OGTT >=11 mmol/l
  • HbA1C samples (Once if symptomatic Twice if asymptomatic) - WHO 2011
    • >=48mmol/mol (6.5%)
    • Not as sensitive as fasting glucose.
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2
Q

In what conditions can HbA1C NOT be used for diagnosis?

A
  1. Type 1 Diabetes - too rapid for HBA1C change
  2. Medication - that raise blood glucose
    • Steroids
    • Antipsychotics
    • Immunosupressants
    • Antiretroviral drugs
  3. Pancreatitis or pancreatic surgery.
  4. Pregnancy - HBA1C lower in pregnancy.
  5. Increased Red Cell Turnover
    • Haemoglobinopathy - Sickle cell, thalassaemia, G6PD, Spherocytosis.
    • Blood loss
  6. Increased RBC lifespan
    • Anaemias - B12/Folic acid & Iron deficiency & their treatment.
    • Splenectomy.
  7. CKD & Renal dialysis - reduced HbA1c especially if treated with erythropoietin.
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3
Q

What are the 2 main types of Impaired Glucose Resistance/Pre-diabetes?

A
  1. Impaired fasting glucose (IFG)
  2. Impaired glucose tolerance (IGT)
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4
Q

What causes impaired fasting glucose?

A

IFG = Hepatic insulin resistance

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5
Q

What is the cause of impaired glucose tolerance?

A

IGT = Muscle insulin resistance

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6
Q

Which patients are more likely to develop CVD, IGT or IFG?

A

Patients with impaired fasting glucose (IFG)

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7
Q

Which patients are more likely to develop T2DM, IFG or IGT?

A

Patients with impaired glucose tolerance. (IGT)

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8
Q

What fasting blood glucose value means you can diagnose impaired fasting glucose (Hepatic resistance)?

A

6.1 to 6.9 mmol/l

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9
Q

What should people with IFG be offered?

A

They should all be offered an Oral Glucose Tolerance Test (OGTT) to rule out both diabetes and IGT.

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10
Q

What blood glucose values do you need to be diagnosed with impaired glucose tolerance (muscle resistance)?

A

Fasting blood glucose < 7.0mmol/l

AND

OGTT 2 hour value - 7.8mmol/l - 11.1mmol/l

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11
Q

What are the normal blood values for fasting, random sugar and HbA1C?

A
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12
Q

How should pre-diabetes be managed?

A
  1. Lifestyle modification
  2. Annual blood test follow up.
  3. Metformin - high risk adults - blood tests show progressing to T2DM despite lifestyle changes.
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13
Q

Steve, how do you remember which diabetes/prediabetes/IGR/IFG/IGT is worse?

A

Normal —>

Pre-diabetes/Impaired Glucose Resistance (IFG–> IGT) –>

T2DM

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14
Q

What HbA1C indicates someone is at high risk of diabetes?

A

HbA1c of 42-47 mmol/mol.

(Between normal and diabetes)

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15
Q

HbA1c reflects the change in blood glucose over what time period?

A

2-3 months though research is pointing to 2 to 4 weeks.

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16
Q

If someone has a high blood sugar and a low HbA1c, what should you expect?

(IGT but HbA1C shows they are not Pre-diabetic)

A

HbA1c is artificially low. Caused by one of the conditions mentioned in previous slide:

  • Lower than expected levels of HbA1c are caused by reduced RBC lifespan:
    • Sickle Cell anaemia, G6PD deficiency or Hereditary spherocytosis.
    • Medication - that raise blood glucose. Steroids, Antipsychotics.

NOTE:

Higher than normal levels of HbA1c (Blood sugar normal but HbA1c high) are caused by increased RBC lifespan:

  • Vitamin B12/Folic acid deficiency
  • Iron-deficiency anaemia
  • Splenectomy