Clinical Review

Metabolic syndrome: When and how to intervene

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Ob/Gyns are in a position to intervene early enough to make a difference in diabetes and heart disease risk—and intervention does reduce risk.


 

References

KEY POINTS
  • First-line therapies for both lipid and nonlipid risk factors? Weight loss and regular exercise.
  • Reduce low-density lipoprotein (LDL) cholesterol to less than 100 mg/dL when metabolic syndrome is present.
  • Lower the total of LDL and very-low-density lipoprotein (VLDL) cholesterol to less than 130 mg/dL, especially in patients with borderline (150 to 199 mg/dL) or high (200 mg/dL or above) triglycerides.
  • When drug intervention is needed to lower non-HDL cholesterol, use an LDL-lowering drug or add nicotinic acid or fibrate to reduce VLDL.
Before you ask why another set of risk factors deserves your attention, consider this: Metabolic syndrome is a veritable epidemic, affecting at least 1 of every 5 patients. Among 60- to 69-year-olds, almost half the population meets the diagnostic criteria.1

This risk are serious. Metabolic syndrome amplifies morbidity and mortality due to diabetes mellitus and cardiovascular disease to such an extent that the National Cholesterol Education Program identifies it as a critical target of risk reduction, second only to reducing low-density lipoprotein (LDL) cholesterol.2

In our primary care capacity, Ob/Gyns are likely to be the first to identify metabolic syndrome and intervene—and intervention makes a difference. An aggressive approach to lipid lowering is critical. However, solid evidence confirms that weight loss and physical activity eliminate some or all of the risk factors in many patients. There’s the challenge. Notably, research reported in theNew England Journal of Medicine found that, with a nutritionist’s guidance, many patients who were counseled about these lifestyle changes reduced their risk of type 2 diabetes by 58% over 3 years.3

This article reviews key studies linking metabolic syndrome to heart disease, diabetes, and death; and describes diagnostic and management fundamentals.

What defines metabolic syndrome?

Women with 3 or more of these factors have metabolic syndrome:

  • Abdominal obesity; ie, waist circumference exceeding 35 inches (88 cm).
  • Triglyceride level of 150 mg/dL or more.
  • High-density lipoprotein (HDL) cholesterol below 50 mg/dL.
  • Blood pressure 130/85 mm Hg or above.
  • Fasting glucose of 100 mg/dL or above.2
Note that lipids should be measured when the patient is in a fasting state.

Women being treated for hypertension or diabetes can be presumed to meet the criteria for those components of metabolic syndrome.

Though the syndrome affects men and women equally overall, Hispanic and African-American women have a 26% and 57% higher incidence, respectively, than men of the same ethnic and racial background.1

Obesity and age drive full-blown syndrome

Insulin resistance, dyslipidemia, and other components of metabolic syndrome exist because of intrinsic genetic susceptibility, which occurs to varying degrees throughout the population.

Some conditions cause this genetic susceptibility to blossom into the full-blown syndrome. Obesity is the driving force for much of this expression.

Age is a highly important factor. Prevalence of metabolic syndrome climbs sharply above the age of 40—in both men and women—so much so that the syndrome is close to becoming the common feature for older age groups (FIGURE 1).

Studies find link to diabetes, cardiovascular disease

What evidence do we have that this syndrome is associated with an increased risk of diabetes, heart disease, and death?

In a study of slightly more than 1,000 males with 10 years of follow-up, Lakka et al4 found a 3.5-fold increased risk of cardiovascular disease mortality with metabolic syndrome. This risk is as high as or higher than the risk for cardiovascular disease in men with type 2 diabetes, which has been described in many other studies.

Risk rises with number of components

A more recent study explored the impact of the number of components of metabolic syndrome present.5 After controlling for age, family history of diabetes, alcohol intake, and cigarette smoking, investigators found a multivariate-adjusted relative risk of cardiovascular disease, compared with an absence of components, of 3.18, 3.48, 12.55, and 14.15 (P<.001 for the presence of and or more components respectively. corresponding relative risks type diabetes were>P<.001>

Another recent study used the coronary artery calcium score as a surrogate for cardiovascular disease.6 This measure is increasingly recognized as a marker of underlying atherosclerosis. In both men and women, the amount of calcium in the coronary arteries increased with the number of metabolic syndrome components.

Dyslipidemia is a critical component

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