Vol. 17 • Issue 4
• Page 45
An estimated 24% of adults in the United States have metabolic syndrome, a condition that increases their risk for coronary heart disease (CHD), stroke and diabetes.1,2Metabolic syndrome is twice as prevalent in Native Americans ages 45 to 49 as it is in the general population falling in this age range.3
Health care for Native Americans and Alaska Natives is provided through the Indian Health Service (IHS), a branch of the Department of Health and Human Services.4In recognition of the high prevalence of metabolic syndrome in Native Americans, the IHS has published protocols for treating it. This article outlines primary features of these protocols.
The Problem
Metabolic syndrome is a cluster of symptoms whose concomitant occurrence increases CHD risk.5It is characterized by increased triglycerides, increased waist circumference, reduced high-density lipoprotein (HDL) levels, hypertension and increased fasting blood glucose. To be diagnosed with metabolic syndrome, a patient must present with three of the five characteristics (see table).6Native Americans are 2.2 times as likely to develop diabetes as non-Hispanic whites.7The prevalence may increase according to degree of Indian heritage. In one study, participants with 100% Indian heritage were 2.5 to 3.5 times more likely to be diagnosed with diabetes than those who had less than 100% Indian heritage.8 The leading cause of death in Native Americans 45 and older is cardiovascular disease. In the general population, it is not the leading cause of death until age 65. Native Americans also have a greater prevalence of hypertension at a younger age.9Obesity is rising among the Native American population as well as the general population.10About 38% of Native Americans 18 and older are overweight.11 besity increases the risk for developing other components of metabolic syndrome. Excess fat leads to decreased insulin sensitivity, which leads to increased insulin secretion.5 etabolic changes related to insulin resistance and hyperinsulinemia lead to dyslipidemia, hypertension, hyperglycemia, type 2 diabetes and CHD.12Metabolic syndrome alerts patients and providers to an increased risk for type 2 diabetes and CHD.12
Risk factors for metabolic syndrome are also appearing in Native American children. One study documented that 33% of Native American children are at risk for being overweight and 19% of these children have a body mass index (BMI) greater than the 95thpercentile.10These children are more likely to be diagnosed with type 2 diabetes at an earlier age. Other cardiovascular risk factors are surfacing at younger ages.13
Cultural Issues
Cultural acceptance of a large body type is a barrier to change for many Native Americans. One study determined that Native American women feel less pressure to maintain a certain body type than their non-Hispanic white counterparts.14
ata show that Native Americans have a significantly lower education level and household income level than the general population living in the same state.15The study also documented an immense need for culturally specific interventions to aid Native American women in achieving the goals of Healthy People 2010.16
lthough broad generalizations are often made about Native Americans, each tribe has its own culture. The 562 federally recognized tribes have an agreement with the federal government to provide health care, but members of these tribes are under the authority of their tribal government as well. Depending on where tribe members live, access to IHS services may be limited or nonexistent. Cultural barriers may also prevent the delivery of appropriate preventive care.17
Traditional healing practices vary by tribe. Investigate and respect them as part of the holistic health plan.18Patients with metabolic syndrome often present with few clear symptoms. Abdominal obesity is the single visible characteristic of this syndrome. Patients with diabetes may complain of fatigue, polyuria, polydipsia and blurred vision. Some patients have no signs of hypertension, and others may have headaches or dizziness.19
erform a complete physical examination that includes waist circumference, blood pressure and lab testing for low-density lipoprotein (LDL), HDL and triglyceride levels.19
Clinical Management
Management of metabolic syndrome in Native Americans begins with an assessment of risk factors. The IHS recommends using a fasting plasma glucose (FPG) for its simplicity and convenience. An FPG level of 100 mg/dL to 125 mg/dL after an 8-hour fast indicates impaired fasting glucose. Start blood glucose analysis at age 18 in patients with any of the following risk factors: body mass index 25 kg/m2or higher, hypertension, low HDL levels, elevated triglycerides, history of gestational diabetes, polycystic ovarian syndrome or family history of type 2 diabetes. Test at least once per year. If these risk factors are not present, diabetes testing should begin at age 35 and be repeated every 3 years.20
IHS has developed a clinical plan for the management of metabolic syndrome. Nutrition, exercise and smoking cessation form the cornerstones.20Medical nutritional therapy is also advised and may require the expertise of a registered dietitian. This therapy emphasizes a reduction in caloric and fat intake through carefully controlled food portions. It also includes a goal of 150 minutes per week of exercise.20
Blood pressure control and lipid reduction should be achieved through lifestyle modifications and, when indicated, pharmacotherapy. Goal blood pressure for patients with metabolic syndrome is less than 140/90 mm Hg. The goal for LDL cholesterol is less than 100 mg/dL for patients with prediabetes and metabolic syndrome but less than 70 mm Hg for patients with diabetes. The goal for triglycerides is less than 150 mg/dL. The IHS protocol contains no goal or treatment regimen for HDL cholesterol.20LDL cholesterol level is a stronger predictor of CHD in Native Americans with diabetes than either HDL cholesterol or triglycerides.21 Weight loss improves features of metabolic syndrome. A weight loss program should be offered to all men with a BMI of 30 or higher and women with a BMI of 25 or higher.22
Patients diagnosed with prediabetes or diabetes should be monitored at least once every6 months. Routine testing of insulin levels, systemic inflammation markers and hemoglobin A1care not part of the IHS management protocol. Hormone level assessment and thyroid function testing should be performed when indicated based on presenting symptoms. Urine microalbuminuria may be helpful in determining the effectiveness of hypertension treatment.20Obtain fasting lipid and triglyceride levels regularly.22 Pharmacotherapy for Native Americans must be based on presenting risk factors.23 HMG-CoA reductase inhibitors, known as the statins, are first-line therapy for dyslipidemia when triglycerides are less than 400 mg/dL. If triglyceride levels exceed 400 mg/dL, a fibrinic acid derivative may be added. Due to concern about glycemic control problems, niacin use is not recommended.22 Obtain baseline liver function tests (LFTs) at the start of treatment and every 6 to 12 months. Discontinue therapy if liver enzymes rise. Statin therapy can decrease cardiovascular disease risk in diabetes patients who do not have high LDL levels.24
Fibrinic acid derivatives should be added when triglyceride levels are high. They may be help raise HDL cholesterol levels, but not lower LDL levels. They should be used in conjunction with another drug when LDL levels are elevated. These drugs accelerate the clearance of very low-density lipoproteins and reduce triglycerides as they facilitate HDL formation.24
In under-60 Native Americans with a BMI of 35 or higher and a fasting blood glucose of 110 mg/dL to 125 mg/dL, metformin (Glucophage) is the drug of choice for prediabetes. Metformin assists with weight loss and type 2 diabetes prevention in these patients.20The IHS treatment algorithm states that patients with metabolic syndrome who have normal creatinine levels, no heart failure and no significant alcohol intake can take metformin.25
Tight blood pressure control decreases cardiovascular disease as much or more than tight glucose control. Angiotensin-converting enzyme (ACE) inhibitors are the preferred method of treatment for Native Americans with diabetes and hypertension.14
diuretic is a common adjunct to an ACE inhibitor. If patients require an additional medication, the IHS recommends adding a diuretic such as hydrochlorothiazide. If the patient still does not reach goal, add a beta blocker or calcium channel blocker.23
Evaluation of Outcomes
In patients with diabetes, Hgb A1cshould be evaluated every 3 to 6 months based. Hgb A1clevels of higher than 7% indicate a need for therapy change. Once treatment goals are met, follow-up visits may be decreased to every 3 to 6 months.26Patients should also receive annual dilated eye exams and dental exams.26
atients with dyslipidemia should be followed based on disease severity. Patients who take statins should have repeat LFTs after 12 weeks of therapy and then annually. In patients taking nicotinic acid, LFT testing should be done at baseline, after 6 to 8 weeks of therapy and annually. To evaluate response, lipid panels should be done every 4 to 6 months.27
Patients with hypertension should be seen frequently until blood pressure is stable. A patient with blood pressure is higher than 140/90 mm Hg warrants specialist consultation.28
Putting It Into Practice
Native Americans face a higher-than-average risk for cardiovascular disease. NPs who treat these patients must be aware of cultural, genetic and environmental factors that influence this risk.
References
1. Centers for Disease Control and Prevention. Prevalence of heart disease - United States, 2005. MMWR. 2007;56(6):113-118.
2. Irwin ML, et al. Physical activity and the metabolic syndrome in a tri-ethnic sample of women. Obes Res. 2002;10(10):1030-1037.
3. Resnick HE, et al. Metabolic syndrome in American Indians. Diabetes Care. 2002;25(7):1246-1247.
4. Indian Health Service. Indian Health Service Introduction. Available at: http://www.ihs.gov/PublicInfo/PublicAffairs/Welcome_Info/IHSintro.asp. Accessed Jan. 26, 2009.
5. Reaven G. Metabolic syndrome: pathophysiology and implications for management of cardiovascular disease. Circulation. 2002;106(3):286-288.
6. American Heart Association. Metabolic syndrome. Available at: http://www.americanheart.org/presenter.jhtml?identifier=534. Accessed Jan. 26, 2009.
7. Centers for Disease Control and Prevention. National diabetes fact sheet: total prevalence of diabetes by race/ethnicity among people aged 20 years or older, United States,2007: American Indians and Alaska Natives. Available at : http://www.cdc.gov/Features/dsDiabetes. Accessed Jan. 26, 2009.
8. Lee ET, et al. Type 2 diabetes and impaired fasting glucose in American Indians aged 5-40 years: the Cherokee diabetes study. Ann Epidemiol. 2004;14(9):696-704.
9. Rhoades DA, et al. Aging and the prevalence of cardiovascular disease risk factors in older American Indians: the Strong Heart Study. J Am Geriatr Soc. 2007;55(1):87-96.
10. Trottier T, et al. Correlates of overweight and obesity in American Indian children. J Pediatr Psychol. Available at: http://jpepsy.oxfordjournals.org/cgi/content/full/jsn047v1?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=american+indian+obesity&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT. Accessed Jan. 26, 2009.
11. U.S. Department of Health and Human Services. Heart Disease and American Indians/Alaskan Natives. Available at: http://www.omhrc.gov/templates/content.aspx?ID=3025. Accessed Jan. 26, 2009.
12. Pi-Sunyer FX. Pathophysiology and long-term management of the metabolic syndrome. Obes Res. 2004;12(suppl):174S-180S.
13. Story M, et al. Obesity in American Indian children: prevalence, consequences, and prevention. Prev Med. 2003;37(6):S3-S12.
14.Thompson JL, et al. Environmental, policy and cultural factors related to physical activity in sedentary American Indian women. Women Health. 2002;36(2):59-74.
15. Giles WH, et al. REACH 2010 surveillance for health status in minority communities - United States. MMWR. 2004;53(6):1-36.
16. Doshi SR, Jiles R. Health Behaviors among American Indian/Alaska Native Women, 1998-2000 BRFSS. J Women's Health. 2006;15(8):919-927.
17. Galloway JM. Cardiovascular health among American Indians and Alaska Natives. Am J Prev Med. 2005;29(5 Suppl 1):11-17.
18. University of Washington Medical Center. Culture clues. Communicating with your American Indian/Alaskan Native Patient. Available at: http://depts.washington.edu/pfes/PDFs/AmericanIndianCultureClue.pdf. Accessed Jan. 26, 2009.
19. National Heart, Lung and Blood Institute. Diseases and Conditions Index: metabolic syndrome. What are the signs and symptoms of metabolic syndrome? Available at: http://www.nhlbi.nih.gov/health/dci/Diseases/ms/ms_signsandsymptoms.html Accessed on Feb 4. Accessed Jan. 26, 2009.
20. Indian Health Services. IHS Guidelines for Care of Adults with Prediabetes and/or the Metabolic Syndrome in Clinical Settings. http://www.ihs.gov/MedicalPrograms/Diabetes/HomeDocs/Tools/ClinicalGuidelines/PreDiabetes_Guidelines_0406.pdf. Accessed Jan. 26, 2009.
21. Russell M, et al. Examination of lower targets for low-density lipoprotein cholesterol and blood pressure in diabetes-the Stop Atheroschlerosis in Native Diabetic Study (SANDS). Am Heart J. 2006;152(5):867-875.
22. Indian Health Service. Indian Health Diabetes Algorithm Cards. Type 2 Diabetes and Hypertension. Available at: http://www.ihs.gov/MedicalPrograms/Diabetes/index.cfm?module=resourcesDTTreatmentAlgorithm. Accessed Jan. 26, 2009.
23. Indian Health Service. Indian Health Diabetes Algorithm Cards. Type 2 Diabetes and Management of Hyperlipidemias. Available at: http://www.ihs.gov/MedicalPrograms/Diabetes/index.cfm?module=resourcesDTTreatmentAlgorithm. Accessed Jan. 26, 2009.
24. Lehne RA. Drugs for asthma. In: Pharmacology for Nursing Care. 6thed. St Louis, Mo.: Saunders Elsevier; 2007.
25. Indian Health Service. Indian Health Diabetes Algorithm Cards. Type 2 Diabetes and Glucose Control. Available at: http://www.ihs.gov/MedicalPrograms/Diabetes/index.cfm?module=resourcesDTTreatmentAlgorithm. Accessed Jan. 26, 2009.
26. Indian Health Service. Standards of care for adults with type 2 diabetes. Available at: http://www.ihs.gov.Medical/Programs/Diabetes/HomeDocs/Tools/ClinicalGuidelines/Standards_Care_0806.pdf. Accessed Jan. 26, 2009
27. Uphold RC, Graham MV. Clinical Guidelines in Family Practice. 4thed. Gainesville, Fla.: Barmarrae Books, Inc.; 2003.
28. Fenstermacher K, Hudson BT. Practice Guidelines for Family Nurse Practitioners. 3rded. Philadelphia, Pa.: Saunders Elsevier; 2004.
Lacey Conaway is a family nurse practitioner at Stigler Health and Wellness Center in Stigler, Okla. Jodie Green is a family nurse practitioner at McAlester Care Associates Urgent Care Clinic in McAlester, Okla.
|