Are there any tests for insulin resistance?

Recognize insulin resistance in practice

(07.03.2005) Insulin resistance (= reduced responsiveness to the hormone insulin) is one of the essential foundations of type 2 diabetes. At the same time, it promotes the development of cardiovascular diseases with threatening consequences such as heart attacks or strokes. Detecting this disorder as early as possible is therefore of crucial importance. However, an exact measurement of insulin resistance is an extremely complex process and can hardly be carried out in practice. For this reason, indirect information such as laboratory values, the medical history of the patient and his family as well as external aspects such as weight and fat distribution patterns are used for the diagnosis.

An international study group recently analyzed data from 2,321 people (183 of them diabetics) from Europe and the USA in order to develop simple decision-making models for insulin resistance diagnostics. In the past, all participants had undergone insulin resistance measurement in the so-called euglycemic-hyperinsulinemic clamp test as part of various clinical studies. At least one in five of the non-diabetics examined (23 percent) turned out to be insulin-resistant. In the group of diabetics, more than 90 percent were affected by insulin resistance.

The clamp test is considered to be the most scientifically sound method for measuring insulin resistance - due to the high cost and time required, however, it is only used in clinical research. The scientists compared the results from the clamp test with various laboratory values, weight and family history of the study participants. They found that, among other things, the values ​​for fasting insulin, body weight in relation to body length (so-called body mass index = BMI), the incidence of diabetes in first-degree relatives and the triglyceride values ​​of a person provide decisive information for the presence of insulin resistance . From this, the study group developed three different decision-making models in order to quickly and easily identify moderate to severe insulin resistance in practice.

Diagnosis based on a blood test (fasting insulin and fasting glucose) and weight:
A simplified method for determining insulin resistance is the so-called HOMA index (HOMA = homeostasis model assessment). To calculate the HOMA index, the values ​​for the fasting insulin and the fasting glucose (mmol / l) are multiplied and the result divided by 22.5.

HOMA index = insulin (µu / ml) x glucose (mmol / l)
22,5

A person is more likely to be insulin resistant if any of the following criteria are met:

  1. HOMA is greater than 4.65 or
  2. HOMA is greater than 3.6 and the BMI is greater than 27.5 kg / m2.

Diagnosis based solely on clinical signs:
A person is more likely to be insulin resistant if any of the following criteria are met:

  1. The BMI is greater than 28.7 kg / m2 or
  2. the BMI is greater than 27.0 kg / m2 and the person has first degree relatives (parents, siblings) with diabetes.

Diagnosis based on a blood test of the fat values:
A person is more likely to be insulin resistant if their triglyceride levels are above 2.44 mmol / L (215 mg / dL).


Dr. med. Anja Lütke, freelancer at the German Diabetes Center at Heinrich Heine University Düsseldorf, German Diabetes Clinic

Source:
Stern SE, Williams K, Ferrannini E et al .: Identification of Individuals With Insulin Resistance Using Routine Clinical Measurements. Diabetes 2005; 54: 333-339