Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome

Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome

Chapter 3

Ronald Goldenberg, Zubin Punthakee

Canadian Diabetes Association 2013 Clinical Practice Guidelines

guidelines.diabetes.ca | 1-800-BANTING (226-8464) | diabetes.caCopyright © 2013 Canadian Diabetes Association

Key Messages

1. Screen wisely. Diagnose precisely.2. Diagnosis of diabetes can be made with:

• Fasting plasma glucose (FPG) level of ≥7.0 mmol/L• 2-hr plasma glucose (2hPG) in 75 g OGTT ≥11.1 mmol/L• A1C ≥6.5%

3. “Prediabetes” ↑ risk of developing diabetes• Impaired fasting glucose (FPG 6.1-6.9 mmol/L)• Impaired glucose tolerance (2hPG 75g OGTT 7.8-11.0)• A1C 6.0- 6.4%

2013

2013


Classification of Diabetes

Type Definition

Type 1 Diabetes Diabetes due to pancreatic beta destruction and prone to ketosis

Type 2 diabetes Diabetes that ranges from insulin resistance with relative insulin deficiency to a predominant secretory defect with insulin resistance

Gestational DiabetesMellitus

Glucose intolerance with onset or first recognition in pregnancy

Other types Variety of uncommon diseases, genetic forms, or diabetes associated with drug use.


FPG ≥7.0 mmol/LFasting = no caloric intake for at least 8 hours

orA1C ≥6.5% (in adults)

Using a standardized, validated assay, in the absence of factors that affect the accuracy of the A1C and not for suspected type 1 diabetes

or2hPG in a 75-g OGTT ≥11.1 mmol/L

orRandom PG ≥11.1 mmol/L

Random= any time of the day, without regard to the interval since the last meal

2hPG = 2-hour plasma glucose; FPG = fasting plasma glucose; OGTT = oral glucose tolerance test; PG = plasma glucose

Diagnosis of Diabetes 2013


Single test in diabetes range

Repeat confirmatory test on different day

Use same test as confirmatory test

Use FPG, A1C or 2hPG OGTT as confirmatory test

Diagnosis made. Repeat not necessary

Symptoms*No symptoms*

If random PG used initially

If FPG, A1C or 2hPG used initially

If results of two different tests are available and both are above the diagnostic cutpoints, the diagnosis of diabetes is confirmed.

2013Diagnosis of Diabetes


Pima Indians

Egyptians

NHANES III

Glycemia and Retinopathy Thresholds

The International Expert Committee. Diabetes Care 2009; 32:1327-1334.

Threshold levels for the development of

retinopathy are similar in all 3 populations: FPG ≥7.0 mmol/L

2hPG ≥11.1 mmol/L A1C ≥6.5%

FPG2hPGHbA1c

70- 89- 93- 97- 100- 105- 116-109- 136- 226-364-244-185-156-138-126-116-106-94-38-

3.4- 4.8- 5.0- 5.2- 5.3- 5.5- 5.7- 6.0- 6.7-HbA1c (%)2hPG (mg/dl)

FPG (mg/dl)Re

tinop

athy

(%)

9.5-

15

10

5

0

FPG2hPGHbA1c

57- 79- 84- 89- 93- 99- 130-108- 178- 258-386-304-218-155-125-110-99-90-80-39-

2.2- 4.7- 4.9- 5.1- 5.4- 5.6- 6.0- 6.9- 8.5-HbA1c (%)2hPG (mg/dl)

FPG (mg/dl)

Retin

opat

hy (%

)

10.3-

50

20

10

0

40

30

FPG2hPGHbA1c

42- 87- 90- 93- 96- 98- 104-101- 109- 120-195-154-133-120-112-102-94-86-75-34-

3.3- 4.9- 5.1- 5.2- 5.4- 5.5- 5.6- 5.7- 5.9-HbA1c (%)2hPG (mg/dl)

FPG (mg/dl)

Retin

opat

hy (%

)

6.2-

15

10

5

0


DETECT-2: A1C ≥6.5% Threshold for Retinopathy

Colagiuri S et al. Diabetes Care 2011; 34:145-150.

Any retinopathy≥ moderate NPDR

4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 15.0+10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5

45403530252015

Prev

alen

ce (%

)

FPG by 0.5 mmol/L intervals

4.0 5.0 6.0 7.0 8.0 9.0 18.0+12.011.0 13.010.0 14.0 15.0 16.0 17.0

Prev

alen

ce (%

)

2hPG by 0.5 mmol/L intervals

4540353025201510

4.0 5.5 6.0 6.5 7.0 7.5 12.0+9.08.5 9.58.0 10.0 10.5 11.0 11.5

Prev

alen

ce (%

)

HbA1c by 0.5% intervals5.04.5

50

4540353025201510

50

50

10


Considerations when using A1C for Diagnosis

• Need validated standardized assay• Repeat confirmatory test on another day• Recognize conditions leading to misleading A1C• A1C is not used for diagnosis in children,

adolescents, pregnancy or suspected type 1 diabetes• Ethnicity and age can affect A1C results

Recognize pitfalls of A1C: conditions that can affect value

Factors affecting A1C

Increased A1C Decreased A1C Variable Change in A1C

Erythropoiesis B12/Fe deficiency Decreased erythropoiesis

Use of EPO, Fe, or B12Reticulocytosis Chronic liver Dx

Altered hemoglobin

Fetal hemoglobin Hemoglobinopathies Methemoglobin

Altered glycation Chronic renal failure ↓↓erythrocyte pH

ASA, vitamin C/E Hemoglobinopathies ↑ erythrocyte pH

Erythrocyte destruction

Splenectomy HemoglobinopathiesChronic renal failureSplenomegalyRheumatoid arthritisHAART meds, RibavirinDapsone

Assays HyperbilirubinemiaCarbamylated HbETOHChronic opiates

Hypertriglyceridemia


Pros and Cons of Diagnostic TestsTest Advantages Disadvantages

FPG Established standardFast and easySingle Sample

Sample not stableDay-to-day variabilityInconvenient to fastGlucose homeostasis in single time point

2hPG in 75 g OGTT

Established standard Sample not stableDay-to-day variabilityInconvenient, UnpalatableCost

A1C ConvenientSingle sampleLow day-to-day variabilityReflects long term [glucose]

$$$Affected by medical conditions, aging, ethnicityStandardized, validated assay requiredNot used for age <18, pregnant women or suspected T1DM


Diagnostic Testing With 3 Different Tests

Dealing with Discordance

• Many people identified as having diabetes using A1C will not be identified as having diabetes by traditional glucose criteria, and vice versa.

• When results of more than one test are available (amongst FPG, A1C, 2hPG in a 75-g OGTT) and the results are discordant, the test whose result is above diagnostic cut-point should be repeated, and the diagnosis made on basis of the repeat test.

FPG 2hPG

A1C


Diagnosis of Prediabetes*Test Result Prediabetes Category

Fasting Plasma Glucose(mmol/L)

6.1 - 6.9

Impaired fasting glucose (IFG)

2-hr Plasma Glucose in a 75-g Oral Glucose Tolerance Test (mmol/L)

7.8 – 11.0 Impaired glucose tolerance (IGT)

GlycatedHemoglobin(A1C) (%)

6.0 - 6.4 Prediabetes

* Prediabetes = IFG, IGT or A1C 6.0 - 6.4% high risk of developing T2DM

2013


A1C Level and Future Risk of Diabetes: Systematic Review

A1C Category (%)5-year incidence of

diabetes

5.0-5.5 <5 to 9%

5.5-6.0 9 to 25%

6.0-6.5 25 to 50%

Zhang X et al. Diabetes Care. 2010;33:1665-1673.


2013

Screening for Type 2 Diabetes in Adults

Algorithm presented on next slides


Screening for Type 2 Diabetes in Adults (continued)

*If both FPG and A1C are available, but discordant, use the test that appears furthest to the right side of the algorithm.


‡ In the absence of symptomatic hyperglycemia, if a single laboratory test is in the diabetes range, a repeat confirmatory laboratory test (FPG, A1C, 2hPG in a 75-g OGTT) must be done on another day. It is preferable that the same test be repeated (in a timely fashion) for confirmation. If results of two different tests are available and both are above the diagnostic cutpoints, the diagnosis of diabetes is confirmed.

‡ Diabetes: In the absence of symptomatic hyperglycemia, if a single laboratory test is in the diabetes range, a repeat confirmatory laboratory test (FPG, A1C, 2hPG in a 75-g OGTT) must be done on another day. It is preferable that the same test be repeated (in a timely fashion) for confirmation. If results of two different tests are available and both are above the diagnostic cutpoints, the diagnosis of diabetes is confirmed.


Definition of Metabolic Syndrome


Recommendation 1

1. Diabetes should be diagnosed by any of the following criteria:• FPG ≥7.0 mmol/L [Grade B, Level 2]

• A1C ≥6.5% (for use in adults in the absence of conditions that affect the accuracy of A1C and not for use in suspected type 1 diabetes) [Grade B, Level 2]

• 2hPG in a 75-g OGTT ≥11.1 mmol/L [Grade B, Level 2]

• Random PG ≥11.1 mmol/L [Grade D, Consensus]

2013


Recommendation 2

2. In the absence of symptomatic hyperglycemia, if a single laboratory test is in the diabetes range, a repeat confirmatory laboratory test (FPG, A1C, 2hPG in

a 75-g OGTT) must be done on another day. It is preferable that the same test be repeated (in a timely fashion) for confirmation, but a random PG in the diabetes range in an asymptomatic individual should be confirmed with an alternate test. Grade D, Consensus.

2013


Recommendation 2 (continued)

2. In the case of symptomatic hyperglycemia, the diagnosis has been made and confirmatory test is not required before treatment is initiated. In individuals in whom type 1 diabetes is likely (younger or lean or symptomatic hyperglycemia, especially with ketonuria or ketonemia), confirmatory testing should not delay initiation of treatment to avoid rapid deterioration. [Grade D, Consensus].

2013


2. If results of two different tests are available and both are above the diagnostic cutpoints, the diagnosis of diabetes is confirmed. Grade D, Consensus.

Recommendation 2 (continued) 2013


Recommendation 3

3. Prediabetes, defined as a state which places individuals at high risk of developing diabetes and its complications, is diagnosed by any of the following criteria: • IFG (FPG 6.1 - 6.9 mmol/L) Grade A, Level 1.

• IGT (2hPG in a 75-g OGTT 7.8 to 11.0 mmol/L) Grade A, Level 1.

• A1C 6.0 - 6.4% (for use in adults in the absence of factors that affect the accuracy of A1C and not for use in suspected type 1 diabetes) Grade B, Level 2 .

2013


CDA Clinical Practice Guidelines

http://guidelines.diabetes.ca – for professionals

1-800-BANTING (226-8464)

http://diabetes.ca – for patients

http://guidelines.diabetes.ca/

http://diabetes.ca/

Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome

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