Diabetes Classifications…

[JITR]

... the condition was recognised during an International Conference not many years ago when the nomenclature of Type 3 (a-k) was developed and you would fall into the proposed Type 3e. Some extracts below:

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Secondary diabetes occurs as a consequence of another medical condition. For example, cystic fibrosis, hemochromatosis, chronic pancreatitis, polycystic ovary syndrome, Cushing’s syndrome, pancreatic cancer, glucagonoma and pancreatectomy. There is also drug induced diabetes which is caused by taking certain medications. For example, corticosteroids (steroid induced diabetes), beta-blockers and thiazide diuretics.​

Usually secondary diabetes is a permanent condition, however in some cases there might be the potential to reverse the effects of hyperglycaemia. The management of secondary diabetes will depend on the condition or medication that has caused it.​

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Then followed the listing for each T3 type, including:​

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Type 3e diabetes. This form of diabetes is any diabetes that has been induced by chemical or drugs. For example, high doses of steroids, taken for an extended period of time, can lead to diabetes developing. Steroid-induced diabetes is therefore a form of type 3e diabetes.​

@Proud to be erratic

Would you be able to share a reference/link to the document containing the excerpts?

 

[Proud to be erratic]

@Proud to be erratic

Would you be able to share a reference/link to the document containing the excerpts?

Hello @JITR,

Apologies for the delay in replying, been busy and distracted since Thursday.

I don't have a reference link; but having seen what I felt was a source document a couple (+/-) of years ago that, alas, I didn't record a reference for and then found some details more recently in a magazine or journal - I did a cut and paste into my phone Notes, which I take extracts from periodically. My IT skills don't go as far as knowing how to condense those notes into a portable document, so I'm copying them verbatim from my notes.

SECONDARY DIABETES

Secondary diabetes occurs as a consequence of another medical condition. For example, cystic fibrosis, hemochromatosis, chronic pancreatitis, polycystic ovary syndrome, Cushing’s syndrome, pancreatic cancer, glucagonoma and pancreatectomy. There is also drug induced diabetes which is caused by taking certain medications. For example, corticosteroids (steroid induced diabetes), beta-blockers and thiazide diuretics.

Usually secondary diabetes is a permanent condition, however in some cases there might be the potential to reverse the effects of hyperglycaemia. The management of secondary diabetes will depend on the condition or medication that has caused it.

Type 3 diabetes

Type 3 diabetes is a name that’s been informally given to the insulin resistance in the brain that can occur in people with Alzheimer’s disease.

People with insulin resistance or type 2 diabetes are 50% and 65% more at risk of developing Alzheimer’s disease, respectively than those without.

The term type 3 diabetes has not been formally recognised and it is best to refer to Alzheimer’s disease as Alzheimer’s disease, to prevent confusion with other types of diabetes such as diabetes type 3a, 3b 3c etc.

Type 3a diabetes. Type 3a diabetes is term designated for any forms of diabetes caused by genetic defects to beta cells (the cells in the pancreas that produce insulin).

Type 3b diabetes. Type 3b is any form of diabetes caused by genetic defects that affect the action of insulin.

Type 3c diabetes. Type 3c diabetes, also known as ‘pancreatogenic diabetes’, is a form of secondary diabetes, that may occur as a result of the pancreatic disorders such as pancreatitis, cystic fibrosis, hemochromatosis, pancreatic cancer, pancreatomy and some neonatal diabetic cases caused by pancreatic agenesis.

Type 3d diabetes. Type 3d is any form of diabetes that results from hormone disorders.

Type 3e diabetes. This form of diabetes is any diabetes that has been induced by chemical or drugs. For example, high doses of steroids, taken for an extended period of time, can lead to diabetes developing. Steroid-induced diabetes is therefore a form of type 3e diabetes.

Type 3f diabetes. This form refers to diabetes that develops as the result of an infection.

Type 3g diabetes. Type 3g refers to less common immune-mediated diabetes.

Type 3h diabetes. This form is for other genetic syndromes that may be associated with diabetes occurring.

There is an anomaly in that I originally noted Type 3 with (a-k) subsidiary categories, and have frequently subsequently referred to (a-k); but I think it's probably only (a-h) and I originally noted that incorrectly. The NHS seems to now unequivocally recognise T3c, but not most of the other then proposed Type 3 subsets. We have recent postings from new members telling us that their HCP doesn't even formally recognise T3c, which is pretty disgraceful considering the NHS does now recognise this distinction. But I guess this is mainly because ICBs have not yet embraced the distinction (perhaps for funding constraints) and some old guard Consultants aren't willing to seperate T3c with full insulin dependence from T1 because the treatment is more or less the same (in their eyes - not mine!)".

So this is what I've found and noted.

 

[JITR]

Thank you so much, @Proud to be erratic, for your notes.

Looking at the International Classification of Diseases (ICD10 and now ICD11) there is more to this than I imagined;
e.g. CLASSIFICATION OF DIABETES MELLITUS 2019

I'd like to comment on your point below about NHS organising itself when I've made some time to look at a few of these documents.

.We have recent postings from new members telling us that their HCP doesn't even formally recognise T3c, which is pretty disgraceful considering the NHS does now recognise this distinction. But I guess this is mainly because ICBs have not yet embraced the distinction (perhaps for funding constraints) and some old guard Consultants aren't willing to seperate T3c with full insulin dependence from T1 because the treatment is more or less the same (in their eyes - not mine!

 

[JITR]

We have recent postings from new members telling us that their HCP doesn't even formally recognise T3c, which is pretty disgraceful considering the NHS does now recognise this distinction. But I guess this is mainly because ICBs have not yet embraced the distinction (perhaps for funding constraints) and some old guard Consultants aren't willing to seperate T3c with full insulin dependence from T1 because the treatment is more or less the same (in their eyes - not mine!

Looking at the International Classification of Diseases (ICD10 and now ICD11) there is more to this than I imagined;
e.g. CLASSIFICATION OF DIABETES MELLITUS 2019. I'd like to comment on your point about NHS organising itself when I've made some time to look at a few of these documents.

Note: placeholder for response - watch this space.

2003 Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus​

2017 Type 3c (pancreatogenic) diabetes mellitus secondary to chronic pancreatitis and pancreatic cancer​

2019 CLASSIFICATION OF DIABETES MELLITUS
2020 WHO Types of Diabetes
2022 NHS Type 3
ICD-10
ICD-11

 

[everydayupsanddowns]

This conversation looks interesting, but it felt better to be moved away from the Insulin Resistance thread so that it doesn’t confuse things there 🙂

 

[JITR]

Agreed. To be continued ...

Short summary: Type 3c has been recognised for 20+ years but not always called Type 3c. WHO came up with a somewhat different classification of diabetic conditions in 2019. This provides for adding extra codes to the original code assigned at diagnosis. The WHO ICD-11 classification is very different from the 10th version that the United States modified to create the ICD-10-CM code set that is used in the US today. One key difference, ICD-11 post-coordinated code clusters, provides a flexible way to represent details about a condition. See ICD-11: Coding of Diabetes

 

[JITR]

Ref:

1. 2003 Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus​

2. 2017 Type 3c (pancreatogenic) diabetes mellitus secondary to chronic pancreatitis and pancreatic cancer​

3. 2019 CLASSIFICATION OF DIABETES MELLITUS
4. 2020 WHO Types of Diabetes
5. 2022 NHS Type 3
6. ICD-10
7. ICD-11

Reading these documents (Ref:1..7) it seems clear that all the forms of diabetes are as difficult to classify as they are to diagnose.

1. 2003 Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus​

"This report is divided into four sections: definition and description of diabetes, classification of the disease, diagnostic criteria, and testing for diabetes.... [It's] aim is to define and describe diabetes as we know it today, present a classification scheme that reflects its etiology and/or pathogenesis, provide guidelines for the diagnosis of the disease ..."

It's worth looking through the report if you want to get a feel for the complexties of diagnosis and classification.

Here, I think, is the section of the classification that refers to Type 3c, although it was not called that in 2003:

C. Diseases of the exocrine pancreas

1. Pancreatitis

2. Trauma/pancreatectomy

3. Neoplasia

4. Cystic fibrosis

5. Hemochromatosis

6. Fibrocalculous pancreatopathy

7. Others

The full classification of diabetes proposed in 2003 is at the end of this post.

2. 2017 Type 3c (pancreatogenic) diabetes mellitus secondary to chronic pancreatitis and pancreatic cancer​

Quote: "Historically, diabetes due to diseases of the exocrine pancreas was described as pancreatogenic or pancreatogenous diabetes mellitus, but recent literature refers to it as type 3c diabetes. The origin of this term is attributed to a table published annually by the American Diabetes Association until 2014,"

The report includes this diagram showing common causes of Type 3c:

(A) Prevalence of type 3c diabetes in a cohort of 1868 participants with diabetes.
(B) Frequency of different causes in the 117 participants with type 3c diabetes.
Reproduced from Ewald and colleagues by permission of John Wiley and Sons.

3. 2019 CLASSIFICATION OF DIABETES MELLITUS
This WHO report paved the way for the transition from ICD-10 to ICD-11. ICD-11 allows for supplementary codes to be added to the initial diagnosis code as other factors are identified.

4. 2020 WHO Types of Diabetes

WHO guidance on the "Diagnosis and management of type 2 diabetes" is based on WHO guidance on diagnosis, classification and management of diabetes.

See page 11 for the the WHO Diabetes classification table.


5. 2022 NHS Type 3

The NHS sometimes refers to Type 3 as Chronic Pancreatitis.
6. ICD-10

2019 version for reference
7. ICD-11

Quote from the homepage:
The next evolution in healthcare.
ICD seamlessly replaces ICD-10, bringing unprecedented accuracy and precision to every health domain. Record every clinical detail effortlessly and embrace modern health concepts that improve outcomes across the board. ICD-11 isn’t just an upgrade—it’s a transformation. With enhanced interoperability, it integrates flawlessly with today’s digital systems, supporting seamless global data exchange.

This article explains ICD-11: Coding of Diabetes. It harks back to Ref 1: 2003 Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus and its full Etiologic classification of diabetes mellitus:

I. Type 1 diabetes* (β-cell destruction, usually leading to absolute insulin deficiency)

A. Immune mediated

B. Idiopathic

II. Type 2 diabetes* (may range from predominantly insulin resistance with relative insulin deficiency to a predominantly secretory defect with insulin resistance)

III. Other specific types

A. Genetic defects of β-cell function

1. Chromosome 12, HNF-1α (MODY3)

2. Chromosome 7, glucokinase (MODY2)

3. Chromosome 20, HNF-4α (MODY1)

4. Mitochondrial DNA

5. Others

B. Genetic defects in insulin action

1. Type A insulin resistance

2. Leprechaunism

3. Rabson-Mendenhall syndrome

4. Lipoatrophic diabetes

5. Others

C. Diseases of the exocrine pancreas

1. Pancreatitis

2. Trauma/pancreatectomy

3. Neoplasia

4. Cystic fibrosis

5. Hemochromatosis

6. Fibrocalculous pancreatopathy

7. Others

D. Endocrinopathies

1. Acromegaly

2. Cushing’s syndrome

3. Glucagonoma

4. Pheochromocytoma

5. Hyperthyroidism

6. Somatostatinoma

7. Aldosteronoma

8. Others

E. Drug- or chemical-induced

1. Vacor

2. Pentamidine

3. Nicotinic acid

4. Glucocorticoids

5. Thyroid hormone

6. Diazoxide

7. β-adrenergic agonists

8. Thiazides

9. Dilantin

10. α-Interferon

11. Others

F. Infections

1. Congenital rubella

2. Cytomegalovirus

3. Others

G. Uncommon forms of immune-mediated diabetes

1. “Stiff-man” syndrome

2. Anti-insulin receptor antibodies

3. Others

H. Other genetic syndromes sometimes associated with diabetes

1. Down’s syndrome

2. Klinefelter’s syndrome

3. Turner’s syndrome

4. Wolfram’s syndrome

5. Friedreich’s ataxia

6. Huntington’s chorea

7. Laurence-Moon-Biedl syndrome

8. Myotonic dystrophy

9. Porphyria

10. Prader-Willi syndrome

11. Others

IV. Gestational diabetes mellitus (GDM)

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