The incidence of type 2 diabetes (T2D) is rising rapidly in the United States. Weight, other lifestyle factors, ethnicity, age, and genetics are significant factors in the development of diabetes. deCODE T2™ is a tool to help you identify patients at higher than average genetic risk — to more effectively target your risk reduction efforts, motivate your patients to take action, and select the best therapeutic approach.
Adjust your patient's lifetime risk of developing type 2 diabetes based on genetic risk markers.
Your patient's combination of genetic variants translates into a relative risk for developing type 2 diabetes that is independent of other risk factors. This may range from 0.6 to 2.2 fold. The genetic risk can then be used to adjust lifetime diabetes risks based on demographic and other factors — such as those shown in the table below.
Remaining Lifetime Diabetes Risk By Age, BMI, Gender, and Race
| Caucasian/White | African/Black | Hispanic | |||||
| Age (years) | BMI (kg/m2) | 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% | 71.2% | 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% | |
In many ways, deCODE T2™ genetic risk assessment is comparable to other widely used risk assessment tests – such as cardiovascular risk based on cholesterol panels and prostate cancer risk based on PSA.
Predict the chance of converting from a pre-diabetic state to type 2 diabetes
The Diabetes Prevention Program, an NIH-sponsored clinical trial that prospectively studied conversion from pre-diabetes to T2D, found that about one-third of pre-diabetics in this study went on to develop T2D within three years. However, among pre-diabetics who carried two copies of the TCF7L2 risk marker (genotype TT), the risk was 1.8 times greater than for those with one or no copies of the marker.1
The study also showed that the increase in risk could be overcome through an effective weight loss regimen. For those who did not lose weight, drug treatment with metformin also reduced progression rates from pre-diabetes to T2D. Identifying individuals with an increased genetic risk may assist you in focusing your most aggressive health promotion efforts and determining who may benefit most from metformin therapy. A known genetic risk could also improve patient motivation to make the lifestyle changes necessary to reduce this risk.
The American Diabetes Association recommends that individuals with impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) be counseled regarding weight loss and increased physical activity. In addition, obese individuals under 60 years at significantly increased risk (due to IGT, IFG, and other factors) are candidates for metformin therapy.2 The markers assessed in the deCODE T2™ may uncover a significantly increased risk that would not otherwise be recognized.
Identify patients who may benefit more from metformin therapy than sulfonylureas
There is evidence that individuals with the T allele for the TCF7L2 marker have a reduced response to sulfonylureas. In one study, 53% of patients on sulfonylurea therapy with the TT genotype failed to reach the target A1C within one year, compared to 40% of people with the CC genotype (homozygous normal).3 TCF7L2 genotype did not significantly impact metformin response, which indicates that those with the TT genotype may respond better to metformin than sulfonylurea therapy.
1. Florez JC, Jablonski KA, N Bayley, et al. TCF7L2 polymorphisms and progression to diabetes in the diabetes prevention pogram. N Engl J Med. 2006;355(3):241-250.
2. American Diabetes Association. Standards of medical care in diabetes—2008. Diabetes Care. 2008;31 Suppl 1:S12-54.
3. Pearson ER, Donnelly LA, Kimber C, Whitley A, Doney AS, McCarthy MI, Hattersley AT, Morris AD, Palmer CN. Variation in TCF7L2 influences therapeutic response to sulfonylureas: a GoDARTs study. Diabetes. 2007;56(8):2178-82.