Q) My endocrinologist (the name we give to doctors who specialize in the endocrine system of the body, the series of glands and the hormones they produce such as insulin and thyroid amongst others) recently told me I had a type of diabetes called latent autoimmune diabetes of adult onset (LADA). I thought there were only 2 types of diabetes. What is this?
A) As our understanding of diabetes expands with each new clinical trial and scientific discovery, researches are arriving at the conclusion that the disease is far more varied in its presentation than first thought and would be better treated if we were more specific in our diagnosis.
Traditionally, diabetics have been classified as type 1, type 2 or gestational diabetics (the term we give to females who become diabetic while pregnant).
Type 1 diabetes is an autoimmune disorder meaning that the disease is caused by your immune system attacking and destroying the beta cells of the pancreas resulting in very little to no insulin being produced. As such, people with type 1 are always insulin dependent. They also tend to be more insulin sensitive then type 2’s who eventually wind up requiring the use of insulin to control their blood sugars. This sensitivity means that doctor’s (or patient’s) should adjust type 1 diabetic’s insulin doses very cautiously as these patients may have dramatic changes in their sugar levels despite only miniscule alterations in their dosage. They tend not to be overweight and are very sensitive to carbohydrates (meaning they are less able to process carbohydrates then most of us resulting in much higher blood glucose swings as a result).
Conversely, patients with type 2 diabetes find their disease develops over a prolonged period of time as they slowly develop either an insulin deficiency or insulin resistance (meaning your body does not respond to insulin as well as it used to) over many years. These people tend to be overweight, have other symptoms of insulin resistance (such as polycystic ovarian syndrome or acanthosis nigricans a skin condition characterized by dark patches developing on the groin, armpits and the back of the neck) and frequently have other family members battling diabetes as well.
Less well known are several other diabetes types. Ketosis-prone diabetes (KPD also formerly known as Flatbush diabetes) is a rare form of diabetes in which despite being classified (by most) as a form of type 2 diabetes these patients initially present with diabetic ketoacidosis which is the most serious low blood sugar emergency we come across in patients with diabetes and is typically seen in our type 1’s due to an overdose of insulin.
People with KPD are typically male and initially are diagnosed around the age of 40. Most are obese and have a family history of type 2 diabetes. Before being admitted with ketoacidosis, most will admit to have been dealing with a recent onset (less than 6 weeks) of frequent urination, excessive thirst and sudden unexplained weight loss.
Most patients with KPD will undergo spontaneous remission requiring the discontinuation of the insulin they would have been started on within a few weeks of diagnosis. However, an estimated 60 to 70% of KPD patients will relapse again (albeit less dramatically this time) and will require either pills or insulin to treat their diabetes from then on.
Latent autoimmune diabetes of adult onset (LADA) is considered to be a subgroup of type 1 diabetes and is frequently misdiagnosed since it typically presents with symptoms of both type 1 and type 2. Like type 1’s, LADA patients tend not to be obese and have antibodies circulating in their blood indicating that their immune system is playing a role in this disorder. However, they resemble type 2’s in that this disorder occurs at an older age of onset and blood work reveals that they are similarly either insulin resistant or deficient.
Patients with LADA typically respond well initially to diet and to the standard diabetic pills but as their beta-cell function declines (much more slowly than with traditional type 1’s but far quicker than seen in type 2’s) their response to these agents will diminish. Most will require insulin within 5 years of diagnosis but many will continue with ineffective pills (for them) for far too long since it so closely resembles type 2.
The last type of diabetes I’d like to talk about (having covered gestational diabetes some time ago in this column and type 3c perhaps best left for a later date) is mild age-related diabetes (MARD). This is a fairly recent term used to describe a large group of type 2 diabetics (maybe as much as 39%) who present at an older age than is seen in the other groups and with a much more benign form of the disease. These patients are less likely to be overweight than other type 2 diabetics and are unlikely to ever require insulin to effectively treat their condition. For many, it is not a bad disease and it can be safely and effectively controlled by a pill such as Metformin with minimal chances of the diabetic complications occurring that others diagnosed in their forties or earlier need to be really concerned about.
The point of having all of these extra subtypes is that they should be treated very differently in order for patients to maintain their health in the long run. Treatment for a typical type 2 should be more aggressive than for a patient with MARD, whereas someone with LADA, will require more extensive monitoring and follow up.
We as a medical community would not be serving these patients properly if we treated them as all the same. As confusing as it can be, the more specific we are in any of our diagnoses, the better the outcomes we should be able to achieve.