IDF and ATP-III definitions of metabolic syndrome in the prediction of all-cause mortality in type 2 diabetic patients

Aim: The metabolic syndrome (MS) is associated with increased cardiovascular morbidity and mortality. Recently, the International Diabetes Federation (IDF) proposed to lower diagnostic thresholds for fasting glucose and waist circumference and to limit the diagnosis of MS only to subjects with abdominal adiposity. The aim of the present study was to assess the prognostic value of IDF criteria in diabetic patients, in comparison with previous ATP-III criteria. Methods: An observational cohort study was performed on a consecutive series of 882 Caucasian type 2 diabetic outpatients, aged 65.3 +/- 10.9 years, with a duration of diabetes of 13.1 +/- 10.6 years. Information on 3-year all-cause mortality was obtained by the City of Florence Registry Office. Results: The prevalence of MS was 68.4 and 73.7% using ATP-III and IDF criteria, respectively. Over the follow-up period, 115 (13.6%) deaths were recorded. Patients with ATP-III-defined MS showed a significantly higher mortality rate when compared with the rest of the sample (16.1% vs. 8.2%; p = 0.002), whereas a non-significant trend was observed using IDF classification (14.9% vs. 10.0%, p = 0.064). At Cox regression analysis, after adjustment for sex, age, and its individual components, diagnosis of MS with ATP-III criteria, but not with IDF criteria [OR (95% CI) 1.65 (0.99-2.72), p = 0.053], was significantly associated with higher mortality [OR (95%,CI) 2.38 [1.18-4.76]). Conclusion: In conclusion, in Caucasian type 2 diabetic patients the application of IDF criteria determines an increase of estimated prevalence of MS, without improving its prognostic value. Further studies are needed before the newer IDF criteria for MS are adopted on a larger scale.