Comparison of coronary heart disease risk assessments among individuals with metabolic syndrome using three diagnostic definitions: a cross-sectional study from China

OBJECTIVE: Metabolic syndrome (MetS) is a notable risk factor of coronary heart disease (CHD). However, there are differences in the methods used to define MetS. The purpose of this study was to determine which MetS definition most fully reflects the 10-year probability of CHD based on the Framingham risk algorithm. DESIGN: Cross-sectional study. SETTING: Data were obtained from the China Health and Nutrition Survey and the Influencing Factors of Chronic Diseases Survey conducted among residents of Nanshan District in Shenzhen, China. PARTICIPANTS: In total, 1721 participants aged 20–80 years were included in this study. METHODS: MetS was diagnosed according to the criteria of the National Cholesterol Education Program’s Adult Treatment Panel (revised NCEP-ATP III), the International Diabetes Federation (IDF) and the Chinese Diabetes Society (CDS). The NCEP-ATP III algorithm was used to calculate the Framingham risk score, and the Framingham risk score was used to define the probability of developing CHD within 10 years either as low (<6%), moderate (6%–10%), moderately high (10%–20%) or high (>20%). Chi-square tests with or without the Bonferroni correction were used to compare the differences in the distribution of the 10-year estimated risk of developing CHD among the three definitions. RESULTS: Compared with the other definitions, the revised NCEP-ATP III criteria identified more participants (30.96%, 95% CI 28.8% to 33.2%) as having MetS, while the CDS criteria showed the highest 10-year probability of developing CHD. The 10-year probability of developing CHD in the participants with MetS was significantly higher than that in the participants without MetS (CDS: χ(2)=157.65, revised ATP III: χ(2)=45.17, IDF: χ(2)=306.15, all p<0.001), and all definitions more fully reflect the CHD risk in men than in women (revised NCEP-ATP III: χ(2)=72.83; IDF: χ(2)=63.60; CDS: χ(2)=23.84; all p<0.001). CONCLUSIONS: This study demonstrates the differences in the prevalence and distribution of the 10-year estimated risk of developing CHD based on the definition of MetS. A significant finding of this study is that the MetS definitions have better performance for men than for women. Further studies in China, especially longitudinal studies, are needed to determine which definition of MetS is best suited for predicting CHD risk.