Comparison of different metabolic syndrome definitions and risks of incident cardiovascular events in the elderly

The metabolic syndrome is associated with increased cardiovascular risk, and its prevalence increases with age. Various definitions of the metabolic syndrome exist, but whether some definitions are more predictive of future cardiovascular events in the elderly is unclear. We compared the risk of incident cardiovascular events in elderly individuals at least 65 years old from the Cardiovascular Health Study with and without the metabolic syndrome as defined by the European Group for the Study of Insulin Resistance (EGIR), National Cholesterol Education Program (NCEP)/American Heart Association (AHA), American Association of Clinical Endocrinologists, International Diabetes Federation (IDF), and modified World Health Organization (WHO) criteria (n = 3390). Participants were without baseline diabetes or cardiovascular disease. Except for EGIR, all definitions of the metabolic syndrome were significantly associated with increased risk of incident cardiovascular (coronary or cerebrovascular) events. Adjusted hazard ratios (HRs) for risk of incident cardiovascular events as defined by the modified WHO, NCEP/AHA, American Association of Clinical Endocrinologists, and IDF criteria ranged from 1.153 (P = .045) for NCEP/AHA to 1.314 (P < .001) for IDF, with 95% confidence interval (CI) ranging from 1.003 to 1.503. Adjusted HR for EGIR was 1.087 (95% CI, 0.908-1.301; P = .362). Similarly, all definitions of the metabolic syndrome were significantly associated with incident coronary events except for the EGIR definition. Only the modified WHO definition was associated with increased risk for cerebrovascular events (adjusted HR, 1.301; 95% CI, 1.038-1.631; P = .022). Although all metabolic syndrome definitions except EGIR were associated with total cardiovascular events and coronary events, only the modified WHO definition was also associated with risk of cerebrovascular events.