25-80% of people with chronic pancreatitis will develop diabetes due to their condition. The specific diabetes is called type 3c diabetes, otherwise known as pancreatogenic diabetes.
What is type 3c diabetes
A healthy pancreas has two functions. The pancreas:
1) controls blood sugar using the hormones insulin and glucagon, and
2) digests food by releasing digestive enzymes
Diabetes is a set of diseases where the first function, blood sugar control, is impaired. Such is the case for type 1 and 2 diabetes.
In contrast, type 3c diabetes causes impairments in both controlling blood sugar and in releasing
digestive enzymes, which can make its treatment more difficult.
Approximately 1.8% of people with adult-onset diabetes likely have type 3c diabetes due to pancreatitis, but many are misdiagnosed as having type 1, or more frequently, type 2 diabetes. This is problematic, because symptoms and treatment can differ, depending on the type of diabetes a person has. In fact, more people are predicted to have type 3c diabetes than type 1 diabetes, and among hospitalized patients, type 3c diabetes patients comprise up to 9.2% of all diabetes patients. 80% of this type of diabetes is caused by chronic pancreatitis, but other conditions can cause it, too, including pancreatic cancer, the genetic condition cystic fibrosis, and haemochromatosis, a genetic condition where iron accumulates over time and causes damage to various organs. The risk of type 3c diabetes is higher in those who smoke, pancreatitis patients with a partial pancreatectomy, and increases in people with chronic pancreatitis over time.
Symptoms of type 3c diabetes, and how they compare to those of type 1 and type 2 diabetes
Blood sugar control
In type 1 diabetes, people are typically dependent on injections of the hormone insulin to help
regulate blood sugar. In type 2 diabetes, people may initially be able to control their blood sugar
with lifestyle changes or medication, but some become insulin-dependent over time.
Individuals with type 3c diabetes are likely to need insulin injections to help control their blood
sugar. About half of people with diabetes due to chronic pancreatitis are treated with insulin
People with type 3c diabetes may have mild impairments with blood sugar control, or may have
more extreme swings in blood sugar, called brittle diabetes. This latter condition may be due to
having impairments in the hormone glucagon or problems with nutrient digestion and
absorption, due to pain or nausea from pancreatitis, or alcohol dependence.
Digestive enzyme impairment
Type 3c diabetes impacts the digestive function of the pancreas, causing a condition called
exocrine pancreatic insufficiency (EPI) in nearly every person with chronic pancreatitis and
diabetes. This can cause symptoms like chronic diarrhea and bloating, and be helped by taking
replacement pancreatic enzymes, called PERT [What You Should Know About EPI].
Digestive symptoms due to EPI are less common in other types of diabetes, but do still occur in
almost one third of type 2 diabetes patients and one to two thirds of type 1 diabetes patients.
How does pancreatitis cause type 3c diabetes?
Over time in chronic pancreatitis the pancreas loses the ability to produce enough insulin, and thus to
control blood sugar. The ability to release enzymes to help digest food also declines in parallel. Scientists
don’t yet understand how this happens, but some preliminary research exists.
It’s possible that the inflammation from the pancreatitis damages the part of the pancreas that releases
insulin, or that the inflammation directly prevents the release of insulin. In later stages of the
pancreatitis, the scarring of the pancreas destroys the insulin-producing parts of the pancreas. It is also
possible that the body becomes less able to use insulin to regulate blood sugar - called “insulin
resistance” - due to chronic pancreatitis over time.
Other causes of diabetes in people with pancreatitis
Rarely, new diabetes in people aged over 50 years turns out to be due to pancreatic cancer. This risk is highest in the first 2-3 years after diagnosis of diabetes. Weight loss at the time of diabetes diagnosis is also more likely in people eventually diagnosed with pancreatic cancer (59%) versus type 2 diabetes (30%). Among all people with new-onset diabetes aged older than 50 (not solely people with pancreatitis), the risk of pancreatic cancer can range from 1% to 13.5%. Nevertheless, the vast majority of people who are diagnosed with new-onset diabetes at those ages solely have diabetes. It should also be noted that individuals with pancreatitis are still able to get type 1 or type 2 diabetes,
independently of their pancreatitis.
Bhattamisra SK, Siang TC, Rong CY, et al. Type-3c Diabetes Mellitus, Diabetes of Exocrine Pancreas - An
Update. Curr Diabetes Rev. 2019;15(5):382-394.
Ewald N, Hardt PD. Diagnosis and treatment of diabetes mellitus in chronic pancreatitis. World J
Ewald N, Kaufmann C, Raspe A, Kloer HU, Bretzel RG, Hardt PD. Prevalence of diabetes mellitus
secondary to pancreatic diseases (type 3c). Diabetes Metab Res Rev. 2012;28(4):338-42.
Hart PA, Bellin MD, Andersen DK, et al. Type 3c (pancreatogenic) diabetes mellitus secondary to chronic
pancreatitis and pancreatic cancer. Lancet Gastroenterol Hepatol. 2016;1(3):226-237.
Singh VK, Haupt ME, Geller DE, Hall JA, Quintana diez PM. Less common etiologies of exocrine
pancreatic insufficiency. World J Gastroenterol. 2017;23(39):7059-7076.
Zhi M, Zhu X, Lugea A, Waldron RT, Pandol SJ, Li L. Incidence of New Onset Diabetes Mellitus Secondary
to Acute Pancreatitis: A Systematic Review and Meta-Analysis. Front Physiol. 2019;10:637.
Whitcomb DC. Pancreatitis: TIGAR-O Version 2 Risk/Etiology Checklist With Topic Reviews, Updates, and
Use Primers. Clin Transl Gastroenterol. 2019;10(6):e00027.
Woodmansey C, Mcgovern AP, Mccullough KA, et al. Incidence, Demographics, and Clinical
Characteristics of Diabetes of the Exocrine Pancreas (Type 3c): A Retrospective Cohort Study. Diabetes