Metabolic Syndrome/Insulin Resistance Syndrome
Julie Adkins, Jill C. Cash, Mellisa A. Hall, Cheryl A. Glass, Angelito Tacderas, and Jenny Nelson Mullen
Definition
A.Metabolic syndrome is an association of several complex disorders: obesity, insulin resistant type 2 diabetes, hypertension (HTN), and hyperlipidemia. This coexistence of conditions leads to atherosclerotic cardiovascular disease (ASCVD). Metabolic syndrome is considered a proinflammatory and prothrombotic state. Elevated triglycerides and low high-density lipoprotein (HDL) cholesterol are strong predictors of vascular events. Triglycerides and the waist circumference are considered the strongest predictors for the development of metabolic syndrome.
B.The inclusion of type 2 diabetes in the definition of metabolic syndrome is debated. Adult Treatment Panel (ATP) III defines metabolic syndrome in adults as the coexistence of any three of five conditions (see Table 24.3).
C.Complications associated with metabolic syndrome include coronary artery disease (CAD), fatty liver disease, cirrhosis, chronic kidney disease, polycystic ovarian syndrome (PCOS), obstructive sleep apnea (OSA), and gout.
D.Metabolic syndrome is noted in the literature under other names, including insulin resistance syndrome and obesity dyslipidemia syndrome. Previously, the term Syndrome X
was used; however, Syndrome X is noted to have normal coronary arteries and the occurrence of angina.
Incidence
A.Demographics data for adults aged 20 to 65 years within U.S. census divisions and regions reported a prevalence of metabolic syndrome between 35% and 40% with the highest rate in the West North Central region. Metabolic syndrome was higher among females (34.4%) than males (29%) and increased with age ≥60 years old (44%).
B.Asians living in the United States and Mexican Americans have the highest age-adjusted prevalence. Among African Americans and Mexican Americans, the prevalence is higher in women than in men.
C.Ethnic background:
1.Native Americans are at the greatest risk (19% prevalence).
2.Mexican Americans have the highest prevalence (31.9%).
3.Black and Hispanic females are 1.5 times more likely than non-Hispanic White females.
Pathogenesis
A.The exact etiology is unknown; however, abdominal obesity has been associated with insulin resistance. Vascular endothelial dysfunction occurs secondary to insulin resistance, hyperglycemia, hyperinsulinemia, and adipokines. Along with high blood pressure (blood pressure) and abnormal lipids, vascular inflammation places the individual at high risk for a cardiovascular insult.
Predisposing Factors
A.Genetic predisposition.
B.Weight gain, especially central/abdominal obesity.
C.Females, especially postmenopausal.
D.Smoking.
E.High-carbohydrate diet, especially soft drink consumption.
F.Lack of exercise:
1.Sedentary lifestyle.
2.Too much television watching by adults.
G.Insulin resistance.
H.Post-traumatic stress disorder (PTSD).
Common Complaints
A.Complaints are all related to the individual coexisting comorbid symptoms.
Other Signs and Symptoms
A.All are related to the individual coexisting comorbid symptoms.
Subjective Data
A.Review the patient’s medical history related to comorbid conditions, including obesity, HTN, and any abnormal laboratory testing (lipids, triglycerides, and glucose tolerance tests [GTTs]).
B.Review the patient’s family history.
C.Review all prescription medications, over-the-counter (OTC) drugs, and herbals.
D.Review the patient’s current level of exercise.
E.Review the patient’s usual diet (24-hour recall), noting high fat and high glucose consumption.
F.Review the patient’s reproductive history.
TABLE 24.3 Adult Treatment Panel III Criteria for Metabolic Syndrome
| Metabolic Syndrome Traits | Definition |
| Central/abdominal obesity | Adult waist circumference: Men >40 inches (102 cm); Women >35 inches (88 cm) |
| Serum triglycerides | Adults: >150 mg/dL or drug treatment for elevated triglycerides |
| Serum HDL cholesterol | Adults: <40 mg/dL in men; <50 mg/dL in women |
| Blood pressure | Adults: >130/85 or drug treatment for hypertension |
| Fasting plasma glucose (FPG) | Adults: >100 mg/dL or drug treatment for elevated blood glucose |
Source: National Institutes of Health. (2002). Third report of the National Cholesterol Education Program (NCEP) expert panel on detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel III): Final report. Bethesda, MD: Author.
Physical Examination
A.Check height, weight, waist circumference, BP, pulse, and respirations.
B.Calculate the BMI and waist-to-hip measurement. Several Internet sites have BMI, body fat, and waist-to-hip ratio calculators.
C.Make general observations for acanthosis nigricans and skin tags (insulin resistance).
D.A full physical examination is guided by the patient’s medical history and presenting signs and symptoms.
Diagnostic Tests
A.Fasting glucose.
B.Fasting lipid panel.
C.Triglycerides.
D.Consider thyroid function.
E.Consider C-reactive protein (CRP; optional).
Differential Diagnoses
A.Metabolic syndrome.
B.Obesity.
C.Hypertension
D.Hyperlipidemia.
E.Elevated-fasting plasma glucose.
Plan
A.General interventions:
Aggressive lifestyle modification focusing on increased physical activity and weight reduction is a cornerstone for treatment.
B.Patient teaching:
1.Dietary recommendations include a low-fat, low-cholesterol, and/or dietary approach to stop hypertension (DASH) diet. Decrease simple sugar and saturated and trans fats and cholesterol (see Appendix B for dietary information).
2.Exercise recommendations include a minimum of 30 minutes a day of walking at a brisk pace or other activity at a moderate intensity. Start by using a pedometer, walking at breaks, or household work.
3.Weight loss of 5% to 10% or more; gradual weight loss of 1 to 2 kg per month. Even small losses are associated with health benefits.
4.BP control strategies include a low-sodium diet (DASH), smoking cessation, and alcohol in moderation.
5.Counsel on smoking cessation.
6.Abdominoplasties do not lower the risk for CAD or insulin sensitivity.
C.Pharmaceutical therapy:
1.Currently, the treatment for metabolic syndrome is to treat each individual component/diagnoses for the individual.
2.Insulin-resistant patients usually are not treated by insulin.
3.Statins are the most common classification used for elevated lipids.
4.A low-dose aspirin may be prescribed related to the patient’s risk of CVDs or prothrombotic state.
5.Oral hypoglycemic agents used to treat type 2 diabetes are not currently recommended for the prevention of metabolic syndrome.
6.HTN should be controlled with appropriate antihypertensives.
Follow-Up
A.Follow-up involves assessing patients for metabolic syndrome at a minimum of 3-year intervals for anyone with one or more risk traits. Follow-up testing includes the following:
1.BMI calculation.
2.Waist-to-hip calculation.
3.Fasting lipid profile.
4.Fasting glucose.
5.BP.
Consultation/Referral
A.Refer to an obstetrician/gynecologist for consultation and management for infertility/pregnancy.
B.Refer to a specialist for any comorbid condition as needed.
Individual Considerations
A.Pregnancy:
1.Specific to their comorbid condition.
B.Geriatrics:
1.Metabolic syndrome has represented a 2.5-fold increase of CVD and a five-fold increase for developing diabetes. Monitoring food choices, weight, and activity/exercise must be added to treatment regimens, lab evaluations, and preventive measures.
2.Traditional risk factors of metabolic syndrome for the general population may differ with geriatrics. Current research is evaluating the reverse epidemiology
or risk factor paradox
where a higher BMI, mild hyperlipidemia, and HTN suggest a better survival during aging. Some studies have shown that a low BP, BMI, and cholesterol give congestive heart failure (CHF) patients a worse prognosis. Currently this intriguing phenomenon is continuing to be investigated.