Classification and criteria of diabetes - Baker Institute J_Classification and... · ‘This led me to suggest that a type of diabetes mellitus might exist which was due, not to lack

Classification and criteria Classification and criteria of diabetes

Jonathan ShawMelbourne, Australia

ClassificationClassification

• Assists with management decisions• Assists with management decisions– E.g. insulin or no insulin

• Informs about disease progress– E.g. is there a risk of DKA?

• Keeps committees busy and keeps clinicians on their toes

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clinicians on their toes

The Ebers Papyrus:  1550 BCEFirst Description of Diabetes

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India 600 BCE: Chakrata and Susruta describe two types of diabetes 

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1936: Himsworth proposed insulin insensitivity as the cause of one type ofinsensitivity as the cause of one type of diabetes

‘This led me to suggest that a type of diabetes mellitus might exist

which was due, not to lack of insulin, but rather to lack of this

sensitising factor.’

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1951: Bornstein shows that the presence or absence of insulin in plasma differentiateabsence of insulin in plasma differentiate between the 2 diabetes types

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WHO and ADA classificationsWHO and ADA classifications• 1965

– 4 types according to age of onset– 7 additional classes

/• 1979/80 – IDDM

NIDDM– NIDDM– other specific aetiological types

• 1997/99• 1997/99– Type 1 diabetes– Type 2 diabetes

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Type 2 diabetes– other specific aetiological types

CLASSIFICATION

Type 1 processType 1 process Type 2 processType 2 process OtherOtherType 1 processType 1 process Type 2 processType 2 process OtherOther

••Classical type 1Classical type 1

••LADALADA

••Type 2 diabetesType 2 diabetes

••Impaired glucose toleranceImpaired glucose tolerance

••Specific causes (Specific causes (egegmonogenic diabetes)monogenic diabetes)

LADALADALatent autoimmuneLatent autoimmunediabetes of adultsdiabetes of adults

Impaired glucose toleranceImpaired glucose tolerance

••Impaired fasting glucoseImpaired fasting glucose

••Gestational diabetesGestational diabetes

••Secondary diabetesSecondary diabetes

••Gestational diabetesGestational diabetes

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Diabetes typesDiabetes types

• Type 1yp

• Type 2

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Diabetes typesDiabetes types

• Type 1• Autoimmune destruction of

pancreatic beta cellsyp• Prone to keto-acidosis• Commonest in children and

teenagers• Can occur at any age

• Type 2 • Require insulin for survival

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Diabetes typesDiabetes types

• Type 1C bi i f i li

yp• Combination of insulin

resistance and secretory defectdefect

• Unusual before the age of 30• Symptoms often minor or

• Type 2y p

absent• May be treated with diet,

bl i liPage 11: Baker IDI

tablets or insulin

Diagnostic criteria for diabetesDiagnostic criteria for diabetes

• FPG ≥7 0 mmol/l• FPG ≥7.0 mmol/lOR Clinical diagnosis • 2hPG ≥11.1 mmol/lOR

requires abnormal tests on 2 separate

days• RPG ≥11.1 mmol/l

days

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Diagnostic criteria for diabetesDiagnostic criteria for diabetes

• FPG ≥7 0 mmol/l• FPG ≥7.0 mmol/lOR Clinical diagnosis • 2hPG ≥11.1 mmol/lOR

requires abnormal tests on 2 separate

days• RPG ≥11.1 mmol/l?OR

days

?OR• HbA1c ≥6.5%

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Potential advantages of HbA1cPotential advantages of HbA1c

• No fasting required• No fasting required

• It is a test of chronic glycaemia, not g yinstantaneous glucose

• It is used to dictate treatment changes• It is used to dictate treatment changes

• Much more reproducible than blood pglucose measurements

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Potential problems for HbA1c in pdiagnosing diabetes• Some people have conditions that• Some people have conditions that

interfere with HbA1c measurementR l li di– Renal or liver disease

– Haemoglobinopathies– Abnormalities of red cell turnover– Iron deficiency

• Ethnic/age differences in glucose-A1c relationship

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Diabetes in pregnancyDiabetes in pregnancy

• High risk mothers – OGTT at 1st visit

• Diagnosis– Fasting glucose ≥ 5.1mmol/L – 1-hr glucose ≥ 10.0mmol/L – 2-hr glucose ≥ 8.5mmol/L

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Screening – essential for early g ydiagnosis• Step 1 non invasive assessment• Step 1 – non-invasive assessment

– AUSDRISK questionnaire

• Step 2 – blood test for those found to be at high risk

• Step 3 – confirmatory blood test for diagnosis

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diagnosis

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