The Metabolic Syndrome: Time for a Critical Appraisal: Joint Statement From the American Diabetes Association and the European Association for the Study of Diabetes

Response to Kahn et al.

We read with interest the American Diabetes Association statement about the metabolic syndrome (1). The idea that the aggregation of borderline risk factors could result in cardiovascular damage equal or superior to that occurring in individuals carrying a full-weight risk factor disease was intriguing. However, this intuition was soon polluted by inclusion of patients with frank diseases. If the philosophy of the metabolic syndrome is to draw firm attention upon “at very high risk” subjects, then the time has come to capture only subjects falling into borderline categorical zones using the Adult Treatment Panel III criteria: fasting glucose levels between 110 and 126 mg/dl, triglycerides between 150 and 200 mg/dl, HDL cholesterol between 30 and 40 mg/dl for men and between 40 and 50 mg/dl for women, blood pressure between 130/80 and 140/90 mmHg, and similar waist circumference values in the absence of obesity (BMI >30 kg/m²). If, however, the basilar concept is the construct of an algebraic hierarchy of risk, the reflections of Kahn et al. (1) claim for the noninferiority of the sum of components versus the whole syndrome. The concept of a “pure” metabolic syndrome, i.e., identifying subjects without frank diseases such as diabetes, obesity, atherogenetic dyslipidemia, and hypertension, would have some benefits: 1) to avoid double-labeled diagnosis, for example diabetes and the metabolic syndrome; 2) to give the real number of subjects at risk and to trace the natural history of the syndrome; and 3) to interfere with its evolution with lifestyle or pharmacological interventions. In the National Health and Nutrition Examination Surveys III sample, ∼8% of coronary heart disease events occurred in people with only borderline levels of multiple risk (2). Moreover, intensive lifestyle intervention (3), diet (4), and drugs (5) have all been shown to be effective in reducing the prevalence of metabolic syndrome, although interventions based on diet, physical activity, and weight reduction seem to work better than drugs. Lastly, it would be easier to force a labeled patient (that with a pure syndrome) to follow advice for lifestyle changes than for unlabeled subjects with one or more borderline risk factors. Since the way to disseminate healthy practices is all but easy, any help is welcome.