Diagnostic Criteria for Metabolic Syndrome
Metabolic syndrome is diagnosed when a patient meets at least 3 of 5 specific criteria, and yes, patients with diabetes can and often do meet the diagnostic criteria for metabolic syndrome. 1
The Five Diagnostic Criteria
The harmonized international definition requires any 3 of the following 5 components for diagnosis: 1, 2
Elevated waist circumference: Population-specific thresholds (≥102 cm in men and ≥88 cm in women for most populations; ≥94 cm in men and ≥80 cm in women for Europeans) 1, 2
Elevated triglycerides: ≥150 mg/dL (1.7 mmol/L) or drug treatment for elevated triglycerides 1, 2
Reduced HDL cholesterol: <40 mg/dL (1.0 mmol/L) in males or <50 mg/dL (1.3 mmol/L) in females, or drug treatment for reduced HDL 1, 2
Elevated blood pressure: Systolic ≥130 mmHg and/or diastolic ≥85 mmHg, or antihypertensive drug treatment in a patient with history of hypertension 1, 2
Elevated fasting glucose: ≥100 mg/dL (5.6 mmol/L) or drug treatment for elevated glucose 1, 2
Metabolic Syndrome in Patients with Diabetes
Most patients with type 2 diabetes will have metabolic syndrome by these criteria. 1 The diagnostic criteria explicitly do not exclude hyperglycemia in the diabetes range as one of the 5 components. 1
A diabetes diagnosis alone does not automatically equal metabolic syndrome—the patient must still meet at least 3 of the 5 criteria total. 1 However, since diabetes fulfills the glucose criterion, the patient only needs 2 additional components (such as elevated blood pressure plus low HDL cholesterol) to meet the diagnosis. 1
Critical Clinical Implications
Patients with diabetes who have metabolic syndrome face substantially higher cardiovascular risk and require aggressive treatment of all metabolic risk factors. 1 The presence of metabolic syndrome in diabetic patients (both type 1 and type 2) indicates higher long-term risk for developing cardiovascular disease. 1
Any diabetic patient with additional metabolic risk factors should receive lifestyle intervention, followed by pharmacologic therapy if necessary, to favorably modify all components of the syndrome. 1
Important Caveats
Patients on drug treatment for any of the metabolic syndrome components are presumed to have that abnormality. 1 For example, a patient taking fibrates or nicotinic acid can be presumed to have high triglycerides and low HDL cholesterol; a patient on antihypertensive therapy counts as having elevated blood pressure; and a patient on glucose-lowering medication counts as having elevated glucose. 1
Abdominal obesity is not mandatory for diagnosis—it is simply one of five equally weighted criteria. 1, 2 This represents the key harmonization between the International Diabetes Federation and American Heart Association/National Heart, Lung, and Blood Institute definitions. 1