Chapter 3 Ronald Goldenberg Zubin Punthakee Canadian Diabetes Association 2013 Clinical Practice Guidelines Key Messages Screen wisely Diagnose precisely Diagnosis of diabetes can be made with ID: 481098
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Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome
Chapter 3Zubin Punthakee MD MSc FRCPC, Ronald Goldenberg MD FRCPC FACE, Pamela Katz MD FRCPC
2018 Clinical Practice GuidelinesSlide2
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Key Changes
No change in the diagnostic criteria New information on methods to differentiate between type 1, type 2 and monogenic diabetes in clinical practice
2018
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide4
Classification of Diabetes
Type
Definition
Type 1 diabetes (including LADA form)
Pancreatic beta cell destruction, usually leading to absolute insulin deficiency
Immune mediated
Idiopathic
Type 2 diabetes
May range from predominantly insulin resistance insulin deficiency to a predominantly secretory defect with insulin resistance
Gestational DiabetesGlucose intolerance with onset or first recognition in pregnancyOther typesVariety of uncommon diseases, genetic forms, or diabetes associated with drug use
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide5
*Neonatal diabetes is a form of diabetes with onset <6 months of age, requires genetic testing, and may be amenable to therapy with oral sulfonylurea in place of insulin therapy
Clinical features
Type 1 diabetes
Type 2 diabetes
Monogenic diabetes
Age of onset (yrs)
Most <25
by can occur at any age (but not before the age of 6 months)
Usually >24 but incidence increasing in adolescents, paralleling increasing rate of obesity in children
& adolescentsUsually <25Neonatal diabetes <6 months* WeightUsually thin, but with obesity epidemic, can have overweight or obesity>90% at least overweightSimilar to general populationIslet auto-antibodiesUsually presentAbsentAbsentC-peptideUndetectable/lowNormal/highNormalInsulin production
Absent
Present
Usually present
First line treatment
Insulin
Non-insulin antihyperglycemic agents, gradual dependence on insulin may occurDepends on subtype of MODYFamily history of diabetesInfrequent (5-10%)Frequent (75-90%)Multigenerational, autosomal pattern of inheritanceDKACommonRareRare (except for neonatal diabetes*)
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome
2018Slide6
Diagnosis of Diabetes
FPG ≥7.0 mmol/L
Fasting = no caloric intake for at least 8 hours
or
A1C ≥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
or
2hPG in a 75 g OGTT ≥11.1 mmol/L
orRandom PG ≥11.1 mmol/LRandom = any time of the day, without regard to the interval since the last meal2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome A1C, glycated hemoglobin; FPG, fasting plasma glucose; PG, plasma glucoseSlide7
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%FPG2hPGHbA1c70-89-93-97-100-105-116-109-136-226-364-244-
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)Retinopathy (%)9.5-15
10
5
0
FPG
2hPG
HbA1c
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)
Retinopathy (%)
10.3-
50
20
10
0
40
30
FPG
2hPG
HbA1c
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)
Retinopathy (%)
6.2-
15
10
5
0
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome
A1C, glycated hemoglobin; FPG, fasting plasma glucose; PG, plasma glucoseSlide8
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
45
40
35
30
25
20
15
Prevalence (%)
FPG by 0.5 mmol/L intervals
4.0
5.0
6.0
7.0
8.0
9.0
18.0+
12.0
11.0
13.0
10.0
14.0
15.0
16.0
17.0
Prevalence (%)
2hPG by 0.5 mmol/L intervals
45
40
35
30
25
20
15
10
4.0
5.5
6.0
6.5
7.0
7.5
12.0+
9.0
8.5
9.5
8.0
10.0
10.5
11.0
11.5
Prevalence (%)
HbA1c by 0.5% intervals
5.0
4.5
5
0
45
40
35
30
25
20
15
10
5
0
5
0
10
A1C, glycated hemoglobin; FPG, fasting plasma glucose; PG, plasma glucoseSlide9
Confirmatory test required
In the absence of symptomatic hyperglycemia, if a single lab test result is in the diabetes range, a
repeat confirmatory lab test
(FPG, A1C, 2hPG in a 75 g OGTT) must be done on another day
Repeat the same test
(in a timely fashion) to confirm
But a random PG in the diabetes range in an asymptomatic individual should be confirmed with an alternate test
If
results of two different tests
are available and both are above the diagnostic thresholds, the diagnosis of diabetes is confirmed2hPG, 2-hour plasma glucose; AlC, glycated hemoglobin; FPG, fasting plasma glucose; OGTT, oral glucose tolerance test; PG, plasma glucose.2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide10
Confirmatory test NOT required
In the case of
symptomatic hyperglycemia
, the diagnosis has been made and a confirmatory test is not required before treatment is initiated.
To avoid rapid metabolic deterioration in individuals in whom
type 1 diabetes is likely
(younger or lean or symptomatic hyperglycemia, especially with ketonuria or ketonemia), the initiation of treatment should not be delayed in order to complete confirmatory testing
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome
2hPG,
2-hour plasma glucose; AlC, glycated hemoglobin; FPG, fasting plasma glucose; OGTT, oral glucose tolerance test; PG, plasma glucose.Slide11
Considerations when using A1C for Diagnosis
Need validated standardized assayRepeat confirmatory test on another dayRecognize conditions leading to misleading A1CA1C is not used for diagnosis in children, adolescents (as the sole diagnostic test), pregnant women as part of routine screening for gestational diabetes, those with cystic fibrosis or those with suspected type 1 diabetes
Ethnicity and age can affect A1C results
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide12
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 B12
Reticulocytosis
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
Hemoglobinopathies
Chronic renal failure
Splenomegaly
Rheumatoid arthritis
HAART meds, Ribavirin
Dapsone
Assays
Hyperbilirubinemia
Carbamylated Hb
ETOH
Chronic opiates
Hypertriglyceridemia
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide13
Pros and Cons of Diagnostic Tests
Test
Advantages
Disadvantages
FPG
Established standard
Fast and easy
Single Sample
Sample not stable
Day-to-day variabilityInconvenient to fastGlucose homeostasis in single time point2hPG in 75 g OGTTEstablished standardSample not stableDay-to-day variabilityInconvenient, UnpalatableCost
A1C
Convenient
Single sample
Low day-to-day variability
Reflects long term glucose
$$$Affected by medical conditions, aging, ethnicityStandardized, validated assay requiredNot applicable to every patient type 2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome A1C, glycated hemoglobin; FPG, fasting plasma glucose; PG, plasma glucoseSlide14
Dealing with discordance in results
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 (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
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome
A1C, glycated hemoglobin; FPG, fasting plasma glucose; OGTT, oral glucose tolerance test; PG, plasma glucoseSlide15
Diagnosis of prediabetes
Tests
Result
Prediabetes category
Fasting plasma glucose (mmol/L)
6.1-6.9
IFG
2h PG
in a 75g OGTT (mmol/L)
7.8-11.0 IGTA1C (%)6.0-6.4Prediabetes2hPG, 2-hour plasma glucose; AlC, glycated hemoglobin; FPG, fasting plasma glucose; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; OGTT, oral glucose tolerance test.2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide16
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.A1C, glycated hemoglobin2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide17
Definition of Metabolic Syndrome
Measure
Categorical thresholds
Elevated waist circumference (population/country specific)
Canada, United States of America
Middle Eastern, Sub-Saharan African, Mediterranean, Europids
Asians, Japanese, South and Central Americans
Men
Women≥102 cm
≥94 cm
≥90 cm
≥88 cm
≥80 cm
≥80 cm
Elevated TG (drug treatment for elevated TG is an alternate indicator†)≥1.7 mmol/L
Reduced HDL-C (drug treatment for reduced HDL-C is an alternate indicator†)
<1.0 mmol/L in males; <1.3 mmol/L in females
Elevated BP (antihypertensive drug treatment in a person with a history of hypertension is an alternate indicator)
systolic ≥130 mmHg or diastolic ≥85 mmHg
Elevated FPG (drug treatment of elevated glucose is an alternate indicator)
≥5.6 mmol/L
Adapted from: Alberti KG, et al.
Circulation
2009;120:1640
† Commonly used drugs for elevated TG and reduced HDL-C are fibrates and nicotinic acid. A person taking one of these drugs can be presumed to have high TG and reduced HDL-C. High-dose omega-3 fatty acids presumes high TGSlide18
Recommendation 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 factors that affect the accuracy of A1C and not for use in those with 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]
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide19
Recommendation 1 cont’d
In the presence of symptoms of hyperglycemia, a single test result in the diabetes range is sufficient to make the diagnosis of diabetes. In the absence of symptoms of hyperglycemia
, if a single laboratory test result is in the diabetes range, a
repeat confirmatory
laboratory test (FPG, A1C, 2hPG in a 75 g OGTT) must be done on another day
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide20
Recommendation 1 cont’d
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. If results of two different tests are available and both are above the diagnostic cut-points, the diagnosis of
diabetes is confirmed
[Grade D, Consensus]
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide21
To avoid rapid metabolic deterioration in individuals in whom
type 1 diabetes is likely (younger or lean or symptomatic hyperglycemia, especially with ketonuria or ketonemia), the initiation of treatment should not be delayed in order to complete confirmatory testing [Grade D, Consensus]
Recommendation 1 cont’d
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide22
Recommendation 2
2. 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 7.8-11.0 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]
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide23
Key Messages
The chronic hyperglycemia of diabetes is associated with significant long-term microvascular and CV complicationsA FPG of ≥7.0 mmol/L, a 2hPG value in a 75 g OGTT of ≥11.1 mmol/L or an A1C of ≥6.5% can predict the development of retinopathy. This permits the diagnosis of diabetes to be made on the basis of each of these parameters
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide24
Key Messages
The term "prediabetes" refers to impaired fasting glucose, impaired glucose tolerance or an A1C of 6.0% to 6.4%, each of which places individuals at increased risk of developing diabetes and its complications
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide25
Key Messages for People with Diabetes
There are two main types of diabetes. Type 1 diabetes occurs when the pancreas is unable to produce insulin. Type 2 diabetes occurs when the pancreas does not produce enough insulin or when the body does not effectively use the insulin that is producedGestational diabetes is a type of diabetes that is first recognized or begins during pregnancy
Monogenic
diabetes is a rare disorder caused by genetic defects of beta cell function
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide26
Key Messages for People with Diabetes
Prediabetes refers to blood glucose levels that are higher than normal, but not yet high enough to be diagnosed as type 2 diabetes. Although not everyone with prediabetes will develop type 2 diabetes, many people willYou should discuss the type of diabetes you have with your diabetes health-care teamThere are several types of blood tests that can be done to determine if a person has diabetes and, in most cases, a confirmatory blood test is required to be sure
2018 Diabetes Canada CPG – Chapter 3. Definition, Diagnosis & Classification of Diabetes, Prediabetes, Metabolic Syndrome Slide27
Visit guidelines.diabetes.ca
Slide28
Or download the AppSlide29
Diabetes Canada Clinical Practice Guidelines
http://guidelines.diabetes.ca – for health-care providers
1-800-BANTING (226-8464)
http://diabetes.ca
– for people with diabetes