Systemic Insulin Resistance
We recognize T1D and BT1D as autoimmune diseases and T2D as resulting from insulin resistance (IR). IR reflects the body’s inability to utilize the hormone insulin effectively, resulting in higher levels of circulating glucose in the bloodstream (hyperglycemia).
People who exhibit IR (also referred to as low insulin sensitivity) require larger doses of insulin in order to achieve glucose homeostasis. As a result, there is a build-up of excess insulin in the blood referred to as hyperinsulinemia. For those with T1D, over the extended duration of the disease, insulinemia has been the perceived cause of a variety of cardiovascular complications, hypertension, osteoporosis and even cancer.
The type 1 diabetic, that exhibits IR, is said to have Double Diabetes.
In the case of both type 1 and brittle type 1 diabetics, the body’s pancreatic beta cells no longer produce insulin and the body becomes dependent on an exogenous (outside) source of the drug for controlling glucose balance. Insulin injections or the use of an insulin pump serve the purpose. The exogenous insulin causes muscle and fat (adipose) cells to take in glucose and utilize it for cellular energy production. It also serves to signal the liver to store excess glucose until needed. The combination of these two events leads to a lowering of blood glucose levels.
IR is not a cause of T1D but does contribute to the erratic BG levels exhibited by the brittle type 1 diabetic. The literature offers a range of 20% to 33% for the prevalence of IR in T1D patients with the percentage increasing, over time, as a function of the rising rate of obesity within the population.
In both T2 and stable T1 diabetics, IR can be managed in two ways: by reducing the need for insulin and increasing cellular activity. The first can be accomplished by altering the diet – reducing carbohydrate intake, especially carbohydrates with high glycemic values. Cellular activity can be increased by exercise or by maintaining an active life style.
The difficulty for the Brittle Diabetic, is that the body does not follow a specific “expected” pattern. Both diet and exercise can result in an unexpected reversal in glucose levels.
The brittle diabetic must learn to become their own best physician. They must understand their body’s response to food and exercise routines. They must learn to read what their body is telling them on a daily basis–it’s going to be a high day or low day - and the struggle for glucose homeostasis is going to require intensive management ( pricking 10+ times).
CAUSES of IR: The causes of IR or the associated risk factors for IR include:
Genetics – gene mutations leading to a genetic predisposition to IR.
Obesity – animal studies have shown a significant increase in IR after being on a high fat diet.
Hypertension, Stress, Lack of exercise or inactive life style, Age, High Cholesterol and a variety of Medications round out the list of causes.
Diagnosis: A physician doesn’t normally test for IR as part of routine care. However, an increase in insulin demand over time by a patient is a strong indicator of IR.
A fasting serum insulin level in excess of 25IU/L is considered insulin resistance.
It was recently found that a mathematical evaluation of the body’s glucose disposal rate (eGDR) serves as a useful clinical tool in determining complication risk assessment in T1D. It takes into consideration three parameters: waist to hip ratio, hypertension (based on BP readings) and HbA1C. The lower the eGDR score, the greater the degree of IR.
eGDR compares favorably to the gold standard evaluation procedure for IR ( “hyperinsulinemia euglycemic clamp”) which is invasive and time consuming.
Treatment: Most people are aware of the use of Metformin to control Type 2 Diabetes. The drug prevents the liver from releasing glucose into the blood stream and increases cellular sensitivity which lowers the body’s demand for more insulin. Metformin is now being prescribed to control type 1 BG levels resulting from IR. Drugs that slow intestinal absorption of sugar, such as Acarbose, have been found effective as well.