Evaluating CMR

IDF clinical tools for diagnosing the metabolic syndrome and type 2 diabetes/CVD risk

In the Hong Kong Cardiovascular Risk Factor Prevalence Study, Cheung et al. (23) studied the association between IDF and NCEP-ATP III metabolic syndrome criteria and diabetes incidence in 1,679 men and women (mean age: 45.1 ± 11.9 years) without diabetes at baseline who were followed for six years. There were 120 new onset diabetes cases during follow-up. The HR for diabetes incidence was 3.5 (95% CI, 2.3-5.2) when IDF clinical criteria were used. The authors suggested that the presence of the metabolic syndrome in someone without diabetes should be a strong warning sign. Moreover, lowering abdominal obesity cut-off values in this Asian population appeared to be justified given that the area under the receiver operating characteristic curves tended to be higher in both men and women when lower waist circumference cut-offs were used.

It is important to mention that although the presence of the metabolic syndrome increases relative risk of CVD/CHD, it diagnosis cannot be used to assess absolute CVD/CHD risk. This can only be done by taking into account traditional CHD risk factors such as age, sex, LDL and HDL cholesterol, blood pressure, smoking, and diabetes. However, clinical diagnosis of the metabolic syndrome can “fine tune” CHD risk prediction on top of traditional risk factors. It is not designed to replace these risk factors, as discussed in other sections.

In summary, IDF clinical criteria for diagnosing the metabolic syndrome include mandatory measurement of waist circumference. Region-specific cut-off values have now been proposed since the relationship of abdominal obesity to CHD or type 2 diabetes varies between ethnic groups. Additional studies are needed to further validate these new criteria and their ties to hard CHD endpoints. Moreover, specific cut-off values will be required for Central American, Sub-Saharan African, and Middle Eastern countries that were not considered in the IDF criteria for lack of specific data.

For more information, please visit the IDF website at http://www.idf.org/home/index.cfm?node=1429