A practical approach to the metabolic syndrome: review of current concepts and management Rajesh Tota-Maharaja,b, Andrew P. Defilippisa, Roger S. Blumenthala and Michael J. Blahaa a Johns Hopkins Ciccarone Preventive Cardiology Center, Johns Hopkins University School of Medicine, Baltimore and bGreater Baltimore Medical Center, Towson, Maryland, USA

Correspondence to Michael J. Blaha, MD, MPH, Blalock 524C Division of Cardiology, 600 North Wolfe Street, Baltimore, MD 21287, USA Tel: +1 410 955 7376; fax: +1 410 614 9190; e-mail: [email protected] Current Opinion in Cardiology 2010, 25:502–512

Purpose of review Novel research over the past 2 years has necessitated an update of our ‘ABCDE’ approach to the metabolic syndrome. Recent findings Clinical trials investigating the role of aspirin in primary prevention have led to an adjustment in the indication for aspirin in metabolic syndrome patients at intermediate risk of a cardiovascular event. There has been renewed enthusiasm for the use of niacin as second-line treatment for atherogenic dyslipidemia, with fibrates reserved for those with severe residual dyslipidemia. In light of the noteworthy findings of the Justification for the Use of statins in Primary Prevention: an Intervention Trial Evaluating Rosuvastatin trial, the ‘C’ category representing ‘cholesterol’ has been expanded to include the use of high-sensitivity C-reactive protein for guiding statin use and perhaps monitoring statin therapy. Recent evidence confirms that diet and exercise continue to be the cornerstone of any metabolic syndrome treatment strategy. Summary The revised ‘ABCDE’ approach incorporates the most recent influential studies into a simple yet thorough algorithm for management of the metabolic syndrome. Keywords ABCDE approach, diabetes mellitus, insulin resistance, metabolic syndrome Curr Opin Cardiol 25:502–512 ß 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins 0268-4705

Introduction The term ‘metabolic syndrome’ has been used to describe the clustering of individual risk factors – including atherogenic dyslipidemia, glucose intolerance, elevated blood pressure (BP), a proinflammatory state, and a prothrombotic state – that result from abdominal obesity and insulin resistance. This article aims to update the 2008 review by Blaha et al. [1] entitled ‘A practical ‘‘ABCDE’’ approach to the metabolic syndrome’ by examining and summarizing important studies over the past 1–2 years as they relate to definition, pathophysiology, assessment, and management of the metabolic syndrome.

Definition Although defining metabolic syndrome as a ‘syndrome’ remains controversial [2], the term continues to effectively alert clinicians to an important patient phenotype [3]. Multiple clinical definitions of the metabolic syndrome have been proposed over the past 11 years [4–6]. The latest convergence of ideas between the American Heart Association and the International Diabetes 0268-4705 ß 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

Federation [7] represents an improvement over previous definitions. In this new definition, the prerequisite of abdominal obesity has been reconsidered. Instead, this criterion is one of the five diagnostic parameters, as insulin resistance and metabolic syndrome can exist in the absence of traditional anthropomorphic measures of obesity. Three of the following five – elevated waist circumference, elevated triglycerides, low high-density lipoprotein (HDL), BP of at least 130/85 mmHg, or fasting glucose of at least 100 mg/dl (5.6 mmol/l) – are required for making the diagnosis (Table 1) [7]. However, dichotomization of the components remains somewhat arbitrary, as insulin resistance, abdominal obesity, and elevated blood glucose are all continuous variables that reflect a graded increase in cardiovascular disease (CVD) and diabetes risk. Hemoglobin (Hb) A1c has not yet been incorporated into the definition, despite its recent inclusion in the criteria for the diagnosis of diabetes mellitus [8]. The metabolic syndrome remains underrecognized, underdiagnosed, and undertreated – perhaps owing to confusion over its exact clinical definition. We believe that a broad approach should be taken in identifying the DOI:10.1097/HCO.0b013e32833cd474

Practical approach to metabolic syndrome Tota-Maharaj et al.

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Table 1 Definition of the metabolic syndrome Definition

Prerequisite for diagnosis

Criteria for diagnosis

WHO [4]

Insulin resistance, plus any two of the following parameters:

NCEP ATP III [5]

At least three out of the following five:

IDF [6]

Abdominal obesity (defined by ethnicity-specific values) plus any two of the following four:

New Consensus definitiona [7]

At least three out of the following five:

Hypertension 140/90 mmHgb Plasma triglycerides 150 mg/dl, low HDL, or both: Men 0.9 WHR Women >0.85 WHR Microalbuminuria Waist circumference: Men 102 cm (40 in.) Women 88 cm (35 in.) Triglycerides 150 mg/dlb HDL-C Men