deCODE T2™
Detects risk of type 2 diabetes independent of family history and obesity. Identifies prediabetics at high near-term risk of conversion to T2D. Predicts responsiveness to major classes of diabetes drugs.
Screening and prevention
How deCODE T2™ can help.
Identifies those at increased risk of T2D.
High-risk individuals may benefit most from aggressive lifestyle modification efforts and/or drug treatment.
Provides more complete risk information.
The genetic risk detected by the deCODE T2™ test is largely independent of any other risk factors that a patient may have. The risk conferred by these other factors can simply be multiplied by the test results to yield a comprehensive risk assessment.
Identifies prediabetics who are at high risk of developing full-blown T2D.
With deCODE T2™ physicians can identify those prediabetic patients who are at a 50-70% likelihood of becoming diabetic within the next 3 to 4 years compared to the baseline risk of 30% in overweight or obese prediabetics.
Enables personalized drug treatment and prevention.
Large-scale, published studies have shown that patients who have the high-risk TCF7L2 genotype detected by the test are likely to respond better to metformin than sulfonylureas. The 2010 ADA recommendations on management of prediabetics state: “In addition to lifestyle counseling, metformin may be considered in those who are at very high risk (combined IFG and IGT plus other risk factors) and who are obese and under 60 years of age.”
Why order deCODE T2™?
- To identify those who are it increased genetic risk for T2D
- To get a more complete relative risk and remaining lifetime risk assessment
- To predict conversion from prediabetes to T2D
- To predict diabetes drug response
Identifying those who are at increased genetic risk of getting T2D.
Knowing and understanding the genetic risk may help implement the strategies that can reduce or minimize the likelihood of an individual developing diabetes. The higher an individual’s risk for T2D is, the more aggressive the prevention strategy should be. Approximately 10% of people of European descent taking deCODE T2™ will receive a score putting them at more than 1.5-times the population average risk of developing T2D. Some 14% of those of East Asian descent and 2% of people of African descent taking the test will be at similarly elevated risk.
More complete relative risk and remaining lifetime risk assessment.
The deCODE T2™ genetic risk profile is largely independent of other risk factors for type 2 diabetes such as family history, obesity and pre-diabetes. The test is therefore useful for patients with or without family history of T2D. The genetic risk can be multiplied by the other risk factors not measured by this test to derive a composite relative risk.
deCODE T2™ thereby identifies those high-risk patients who may benefit the most from more aggressive management, either through lifestyle modification or drug treatment.
In addition to providing the risk of T2D relative to the general population the deCODE T2™ test report provides a lookup table based on epidemiological studies to calculate the remaining lifetime risk of T2D according to the current age of the patient.
Remaining lifetime risk
The remaining lifetime risk is defined as the risk of developing T2D after a certain age, assuming the patient has not already been diagnosed with T2D. It is dependent on known risk factors, such as obesity, ethnicity, family history, prediabetes, and age(1). The genetic risk identified by the deCODE T2™ test is largely independent of any other risk factors that the patient may have and therefore may be multiplied by the relative risks conferred by these other factors.
The remaining lifetime risk for an individual (table) can be multiplied by the combined genetic risk identified by deCODE T2™ profile to obtain his/her remaining lifetime risk. For example, for an overweight white male who is 45 years of age, the remaining lifetime risk according to the table is 23.7%. If his deCODE T2™ result is 1.8, his remaining lifetime risk will increase to 42.6%.
| Remaining lifetime risk (%) | |||||||
|---|---|---|---|---|---|---|---|
| Age | BMI (kg/m2) | White | Black | Hispanic | |||
| Male | Female | Male | Female | Male | Female | ||
| 18 | <18.5 | 6.2 | 9.8 | 9.0 | 14.9 | 9.7 | 15.5 |
| 18.5 to <25 | 16.9 | 14.5 | 21.4 | 18.4 | 25.0 | 21.5 | |
| 25 to <30 | 25.5 | 30.7 | 33.1 | 39.3 | 36.9 | 43.4 | |
| 30 to <35 | 51.8 | 48.8 | 61.3 | 60.1 | 68.1 | 66.0 | |
| 35+ | 66.1 | 69.3 | 72.9 | 79.8 | 81.1 | 86.0 | |
| 45 | <18.5 | 6.0 | 9.1 | 9.2 | 14.1 | 9.3 | 14.0 |
| 18.5 to <25 | 15.9 | 13.2 | 20.7 | 16.7 | 23.3 | 18.9 | |
| 25 to <30 | 23.7 | 27.5 | 31.7 | 35.6 | 33.8 | 38.0 | |
| 30 to <35 | 47.5 | 42.2 | 59.2 | 53.4 | 62.9 | 56.4 | |
| 35+ | 59.4 | 58.4 | 71.0 | 72.2 | 75.6 | 74.5 | |
| 65 | <18.5 | 2.1 | 3.5 | 2.5 | 4.2 | 3.0 | 4.9 |
| 18.5 to <25 | 10.2 | 9.0 | 10.3 | 8.7 | 14.0 | 11.9 | |
| 25 to <30 | 13.8 | 17.3 | 14.4 | 17.5 | 18.6 | 22.5 | |
| 30 to <35 | 28.3 | 26.3 | 29.8 | 26.9 | 37.2 | 33.8 | |
| 35+ | 33.2 | 34.9 | 35.2 | 35.7 | 43.6 | 44.3 | |
deCODE T2™ predicts pre-diabetes conversion and diabetes drug response.
deCODE T2™ enables physicians to determine which of their prediabetic patients are at 50 to 70% absolute risk of converting to T2D within 3 to 4 years. The average baseline risk of conversion in overweight or obese prediabetics is 30%.
deCODE T2™ is one of the strongest indicators for conversion to T2D.
It identifies those with the greatest need for, and who may benefit most from, preventive management, as well as predicting those who are more likely to respond to metformin than sulfonylureas. Patients who have the high-risk TCF7L2 genotype are likely to respond better to metformin than sulfonylureas.
Studies in two populations of European descent show that T2D patients who are homozygous TT at TCF7L2 have much lower response to sulfonylureas compared to those who are not TT homozygous; with only 36% of TT homozygotes meeting HbA1C target of 7% or lower, versus 62% of those who were not TT homozygous(2,3). Metformin response, on the other hand, did not depend on the TCF7L2 genotype, meaning that patients who have the TT TCF7L2 genotype were likely to respond better to metformin than sulfonylureas.
The 2010 ADA recommendations on management of prediabetics state: “In addition to lifestyle counseling, metformin may be considered in those who are at very high risk (combined IFG and IGT plus other risk factors) and who are obese and under 60 years of age.”
Empowering information
Lifestyle modification leading to a healthier diet, more exercise and, most importantly, weight loss, is the mainstay of T2D prevention. Personal information on risk and the consequences of developing T2D are principal tools for motivating patients to change their lifestyle. The personal genetic risk identified by deCODEme™ can give people additional incentive to comply with recommendations.
deCODE T2™ provides a new and an important component to the process of identifying those who are at elevated risk of developing T2D, independent of other risk factors, as well as those prediabetics most likely to progress to full-blown T2D.
It identifies those who are at highest risk, and who may therefore benefit most from aggressive nutritional advice and lifestyle interventions. This holds especially for those who already have prediabetes and may be candidates for metformin treatment when lifestyle changes and weight loss are not sufficiently successful.
Professionals who practice preventive medicine for T2D encounter multiple patients with well known risk factors for T2D. These risk factors include family history, obesity, ethnicity, and history of gestational diabetes, and these people need to lose weight, get more exercise and improve their diet. Additionally there are those patients who already are prediabetic, which itself is a big risk factor for T2D. But efforts to get patients to change their lifestyle and address known risk factors for T2D are often unsuccessful. Additional information on which patients have increased genetic risk may give physicians’ advice greater weight and specificity, and provide the patients added incentive to implement and stick to lifestyle modification regimes that can reduce their chances of becoming diabetic. Furthermore, knowing which prediabetic patients are at greater risk of progressing to T2D makes it possible to apply more focused and more intensive efforts and to identify those for whom medication might be useful.
The risk can be overcome – preventive measures work.
Both the U.S. government-supported clinical trial involving prediabetics, the Diabetes Prevention Program study, and the European DPS study(4,5) have shown that weight loss programs worked as well if not better for patients at highest genetic risk for conversion. Effective weight loss reduced conversion to T2D by over 60%. The U.S. study also demonstrated that even in those who did not lose weight, drug treatment with metformin also reduced progression rates of prediabetics to T2D(4).
Published studies have shown that certain medications do appear to effectively slow the rate of progression from prediabetes to T2D. The 2002 Diabetes Prevention Program study showed that metformin could decrease conversion by 31% overall and at an even higher rate in patients younger than 60(6). The 2010 ADA guidelines state: “In addition to lifestyle counselling, metformin may be considered in those who are at very high risk (combined IFG and IGT plus other risk factors) and who are obese and under 60 years of age.”
This content was last reviewed on March 16, 2011.