It’s not Type 1…and it’s not Type 2. When researchers from the UK’s University of Surrey checked the health records of 2.3 million adults for a new study published in the November issue of Diabetes Care, they uncovered more cases than expected of a little-known blood sugar problem: Diabetes type 3c. And most were misdiagnosed, meaning people with “3c” may not have gotten the best treatment.
Type 3c is “diabetes that acts differently,” according to study co-author Andrew McGovern, a research fellow at the University of Exeter and honorary clinical researcher at the University of Surrey. It’s caused by damage to the pancreas—the gland that contains insulin-producing islet cells—from inflammation (pancreatitis), surgery or cancer. The damage knocks out some, but not all, islet cells, reducing insulin levels in the body. In contrast, type 1 diabetes is triggered by an immune-system attack that knocks out virtually all of a person’s islet cells and type 2 happens when the pancreas can’t make enough insulin to overcome insulin resistance.
The study looked at new cases of diabetes. It found 559 people with probable type 3c. It was more common than new type 1 diabetes in adults (354 had that type), which surprised the researchers. More concerning: 88% with type 3c were misdiagnosed as type 2s. That’s a problem, because conventional type 2 drugs that boost insulin sensitivity and insulin production may not work well for 3cs. They were “twice as likely to have poor blood sugar control as those with type 2 diabetes,” McGovern says. “They were also five to ten times more likely to need insulin.”
Getting the wrong diagnosis can waste time and money and leave 3c’s exposed to high blood glucose levels longer, boosting the risk for complications. “Our findings highlight the urgent need for improved recognition and diagnosis of this surprisingly common type of diabetes,” he notes.
But the connection between pancreas trouble and rising blood sugar isn’t always obvious. It can take years for diabetes to develop after an attack of acute pancreatitis, or after a long-running battle with chronic pancreatitis, or after treatment for tumors. “The majority of people who have had an episode of pancreatic inflammation will be aware of it. It often requires an admission to hospital and can be easily diagnosed from a blood test (blood amylase levels) at the time of symptoms,” McGovern says. “However people who have gone on to develop diabetes a decade or more lately are unlikely to link the two conditions.”
An estimated 210,000 Americans land in the hospital each year with a painful attack of acute pancreatitis—often caused by gallstones, long-term heavy alcohol use, infections and abdominal injuries. It can become chronic, especially in heavy drinkers and in those with cystic fibrosis. In addition, about 53,670 people develop pancreatic cancer each year. The researchers recommend that doctors ask their patients with diabetes about any history of pancreas problems, even if it happened long ago or just once. The answer could improve your diabetes care plan and your health. You may need insulin sooner, for instance. “People who have had a single episode of pancreatic inflammation have the mildest form (around 5 times more likely to need early insulin than people with type 2) whereas those with long-standing pancreatic inflammation were around 10 times more likely to need early insulin,” McGovern notes.
“Labelling someone as having type 3c diabetes should also lead clinicians to think about the digestive functions of the pancreas (which are not usually impaired in people with type 1 or type 2 diabetes),” he says. “Because of a lack of some digestive enzymes from the pancreas people with type 3c diabetes can develop abdominal pain, diarrhea or loose stools, and some vitamin deficiencies.” Your doctor may recommend digestive enzymes and/or other supplements.
The researchers hope to look next at how to identify type 3cs—and at whether type 2 drugs can help. “Which ones work well and which don't has yet to be determined,” he says.
Certified diabetes educator and EndocrineWeb advisor Amy Hess-Fischl, MS, RD, LDN, BC-ADM, CDE, of the Kovler Diabetes Center in Chicago, notes that the study data may not reflect the situation in other countries because it focused on UK residents. Knowing about the connection between pancreas damage and diabetes can be important if it leads to better care, she says.
But a bigger issue for most people with diabetes is that they “don’t meet the current American Diabetes Association A1c goal of less than 7%. Regardless of the type you have, you need to have a conversation with your healthcare provider to help you get there, with additional medications or insulin and a referral to a diabetes self-management class and nutrition education,” Hess says. “Most people diagnosed with type 2 wait too long to start insulin.”