Have you been misdiagnosed with type 2 diabetes?
Medichecks medical director Dr Sam Rodgers discusses how it is possible for type 1 diabetes to be misdiagnosed as type 2 and the warning signs to look out for.
There are two types of diabetes, type 1 which has long been thought to occur in childhood and young adulthood and type 2 diabetes which tends to develop in later life. Type 1 diabetes is caused by the immune system attacking the pancreas and destroying the cells that produce insulin, because of this it tends to develop quickly, and can cause serious complications if it is missed. Type 2 diabetes develops more slowly and the usual cause for this is increasing obesity. Body fat (particularly in the waist area) causes resistance to the body’s own insulin. In type 2 the pancreas is still working hard to produce insulin but the body tissues stop listening to it and control over blood glucose suffers.
A recent study has found that the assumption that type 1 diabetes is a disease that develops primarily in children and young adults is wrong. In fact, the number of new cases per year in children and younger adults is similar to the number of new cases in older adults (31 to 60 year olds). Because type 2 diabetes is so much more common many of these adults with type 1 diabetes risk being diagnosed with type 2 initially, with the diagnosis of type 1 being made after they don’t respond to treatments for type 2 diabetes. Sometimes serious complications such as diabetic ketoacidosis, which can result in coma, lead to the original diagnosis being questioned.
To give you some idea of how easy it is for this to happen prime minister Theresa May was initially diagnosed with type 2 diabetes, but when her medications did not work and other symptoms such as excessive thirst and losing weight developed it became clear that she actually had type 1 diabetes. 42% of new cases of type 1 diabetes were found to develop after the age of 30, so the prevailing belief that it is a condition which affects only the young is wrong. The authors of the study could only find ten previous scientific papers looking at how many new cases of type 1 diabetes develop in later life. This is a vanishingly small amount for such a serious and relatively common condition, reflecting low levels of awareness in the scientific community about late-onset type 1 diabetes.
The study looked at several genes that predispose to type 1 diabetes, and this raises the possibility that genetic testing will help to distinguish type 1 diabetes from type 2 diabetes in the future.
There are some clues that a recently diagnosed type 2 diabetic may be more likely to have type 1 diabetes. Someone who is slim, who does not have other risks for metabolic problems (such as polycystic ovarian syndrome or a family history of diabetes) and who is struggling to control their diabetes with type 2 medications such as metformin or gliclazide raises concerns about the possibility of type 1 diabetes. While there are tests available to help distinguish whether a type 2 diabetic is more likely to have type 1 diabetes these have some fairly significant limitations that mean they should be interpreted with caution.
Currently, the best indication that a diagnosis of type 2 diabetes may be incorrect is how well someone is responding to medication, and whether they have a normal body mass index. Someone whose body mass index is below 25 is less likely to develop type 2 diabetes than someone who is overweight. If you have recently been diagnosed with diabetes and fit this description then you should discuss the possibility of late-onset type 1 diabetes with your GP or diabetologist.