AUTHORS: Harikrashna B. Bhatt, MD and Russell E. Bratman, MD and Kaushal B. Jani, MD
Metabolic syndrome refers to a constellation of risk factors for development of cardiovascular disease and type 2 diabetes mellitus. Hyperglycemia, dyslipidemia, abdominal obesity, and hypertension are critical components of metabolic syndrome. Over the years, many definitions of the syndrome have been proposed and debated (see Table E1). In 2009, a consensus statement defined “metabolic syndrome” as the presence of any three of the following criteria.1
- Abdominal waist circumference >94 cm (37 in) in men and >80 cm (31 in) in women (the use of population- and country-specific definitions is suggested; however, until better data are available, The International Diabetes Federation [IDF] recommends using these cutoffs)
- Serum hypertriglyceridemia ≥150 mg/dl (1.7 mmol/L) or drug treatment for elevated triglycerides
- Serum high-density lipoprotein (HDL) cholesterol <40 mg/dl (1 mmol/L) in men and <50 mg/dl (1.3 mmol/L) in women or drug treatment for low HDL-C
- Blood pressure ≥130/85 mm Hg or drug treatment for elevated blood pressure
- Fasting glucose ≥100 mg/dl (5.6 mmol/L) or drug treatment for elevated blood glucose
TABLE E1 Common Definitions for Metabolic Syndrome
| Criterion | NCEP ATP III (3 or more criteria) | ||
|---|---|---|---|
| Abdominal obesity | Waist circumference | ||
| Men | >40 inches (>102 cm) | ||
| Women | >35 inches (>88 cm) | ||
| Hypertriglyceridemia | >150 mg/dl (≥1.7 mmol/L) | ||
| Low HDL | |||
| Men | <40 mg/dl (<1.03 mmol/L) | ||
| Women | <50 mg/dl (<1.30 mmol/L) | ||
| Hypertension | ≥130/85 mm Hg or on antihypertensive medication | ||
| Impaired fasting glucose or diabetes | >100 mg/dl (5.6 mmol/L) or taking insulin or hypoglycemic medication |
ATP, Adult Treatment Panel; HDL, high-density lipoprotein; NCEP, National Cholesterol Education Program.
From Floege J et al: Comprehensive clinical nephrology, ed 4, Philadelphia, 2010, Saunders.
- Affects close to 25% of U.S. adults.
- Prevalence increases with age, affecting more than 40% of individuals >60 yr.
- Increasing prevalence among women, especially in the African American and Mexican American populations.
- Prevalence increases with weight. Metabolic syndrome is noted in 5% of normal weight, 22% of overweight, and 60% of obese individuals.
- Other risk factors include low socioeconomic status, lack of physical activity, high-carbohydrate diet, alcohol intake, smoking, genetic predisposition, use of atypical antipsychotics, and postmenopausal status.
- Obesity, hypertension, dyslipidemia, and hyperglycemia as defined.
- Patients with metabolic syndrome are at twice the risk of developing cardiovascular disease and have a sevenfold increase in risk for type 2 diabetes and a one-point-fivefold increase in all-cause mortality compared to patients without the syndrome. Other complications include cognitive decline in the elderly, fatty liver disease, polycystic ovary syndrome, obstructive sleep apnea, gout, and chronic kidney disease.
- Focus history on symptoms of diabetes and its complications, obesity and its complications, coronary artery disease (angina), and polycystic ovary syndrome.
- Complete physical examination, including height, weight, waist circumference, and blood pressure.
- Genetic and environmental factors associated with obesity increase the risk of developing metabolic syndrome.
- Abdominal obesity is associated with insulin resistance and hyperinsulinemia.
- Insulin resistance results in ineffective glucose utilization, eventually leading to type 2 diabetes mellitus.
- Hyperinsulinemia and inflammatory markers/cytokines play an important role in development of abnormal lipid profile, hypertension, and vascular endothelial dysfunction, which can lead to the development of atherosclerotic cardiovascular disease.
