Glucose tolerance status is a better predictor of diabetes and cardiovascular outcomes than metabolic syndrome: a prospective cohort study

A prospective cohort study was conducted with subjects regularly attending the primary care unit of Hospital de Clínicas de Porto Alegre. Participants underwent a 75？g OGTT. Metabolic syndrome definition was based on the criteria of IDF/AHA/NHLBI-2010.Participants mean age was 61？±？12？years (males: 38%; whites: 67%). Of the 148 subjects included, 127 (86%) were followed for 36？±？14？months, 21 (14%) were lost. Subjects were classified into four groups based on baseline OGTT: 29% normal (n？=？43), 28% impaired fasting glucose (IFG; n？=？42), 26% impaired glucose tolerance (IGT; n？=？38), and 17% diabetes (n？=？25). Metabolic syndrome prevalence was lower in normal group (28%), intermediate in IFG (62%) and IGT (65%) groups, and higher among subjects with diabetes (92%; P <0.001). Incidence of diabetes increased along with the stages of glucose metabolism disturbance (normal: 0%, IFG: 16%, IGT: 28%; P？=？0.004). No patient with normal OGTT developed diabetes, regardless metabolic syndrome presence. Diabetes at baseline was the major determinant of cardiovascular disease occurrence (normal: 0%, IFG: 4%, IGT: 0%, diabetes: 24%; P？=？0.001). In Cox-regression analysis, only the 2？h OGTT results were associated with diabetes (OR？=？1.03; 95%CI 1.01–1.06; P <0.001) and cardiovascular disease development (OR？=？1.013; 95%CI 1.002–1.025; P？=？0.024).In this sample of subjects undergoing diabetes screening, the OGTT predicted diabetes and cardiovascular disease more effectively than the metabolic syndrome status.Hyperglycemia is a well-known risk factor for micro- and macrovascular disease [1] and is associated with increased morbidity and mortality [2,3]. Alterations on glucose homeostasis have been described preceding diabetes mellitus (DM) diagnosis, and are known as “prediabetes”. Prediabetes comprises two subcategories, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), classified based on glucose levels at fasting and after a glucose challenge (oral glucose tole