Volume 01, Issue 03

May 6, 2010

Cardiometabolic Risk

Beyond Metabolic Syndrome

Interview with:

Peter Sheehan, MD, President, Sheehan Health Management Consulting, LLC, New York, NY

Definition of risk

Although many clinicians have become familiar with the term “metabolic syndrome,” the definition does not adequately encapsulate the various factors that contribute to risk for cardiovascular disease (CVD). Therefore, the American Diabetes Association (ADA) promotes using the term “cardiometabolic risk.”

Metabolic syndrome

A person is considered to have the metabolic syndrome if he or she has ³3 of the following risk factors: 

Overweight or obesity

•   Glucose intolerance

•   Hypertension

•   High level of triglycerides

•   Low level of high-density lipoprotein (HDL) cholesterol

Additional cardiometabolic risk factors

Nonmodifiable Age

•   Race

•   Sex

•   Family history

Modifiable 

•   Inflammation

•   Hypercoagulation

•   Smoking status

•   Physical inactivity

Gestational diabetes (GDM)

Women with histories of GDM are not only at increased risk of developing overt type 2 diabetes, but also are at increased risk of developing CVD. Furthermore, it appears that children of these women also have elevated risk of developing metabolic abnormalities (eg, central obesity; high levels of triglycerides) at a young age.

Risk factor management

Focus: smoking cessation; lipid control; blood pressure (BP) control, glycemic control; antiplatelet ther­apy; (see issues 01 and 02 for updated clinical practice guidelines).

Smoking cessation: A variety of pharmacologic agents are available (eg, varenicline; nicotine replacement therapy) and help improve quit rates.

LDL-cholesterol: Therapy — primarily statin therapy. Targets — low-density lipoprotein (LDL) cholesterol <100 mg/dL for individuals with ³2 cardiometabolic risk factors; LDL cholesterol <70 mg/dL for those with diabetes and established CVD.

Apolipoprotein B (Apo B): Measurement provides an indication of the number of atherogenic lipid parti­cles, because it occurs in a one-to-one ratio with LDL and very-low density lipoprotein (VLDL) choles­terol. Targets — <80 mg/dL for patients with high cardiometabolic risk; <90 mg/dL for those at moderate risk. Implications — LDL particles are not uniform in size or density. For a given level of LDL choles­terol, a high density of particles (ie, small, dense particles) is associated with a high degree of atheroge­nicity, whereas a low density of particles (ie, large, “fluffy” particles) is associated with a low degree of atherogenicity.

Non–HDL-cholesterol: Total cholesterol minus HDL-cholesterol seems to be more closely correlated with risk for CVD than is LDL-cholesterol.

Prioritizing management approaches to reduce cardiometabolic risk

•   Primary: Physical activity (eg, 30 min/day of walking) and dietary interventions are critical components in the management of cardiometabolic risk — especially in patients who are overweight or obese and have multiple risk factors. In patients with type 2 diabetes, weight loss may have a greater impact on car­diometabolic risk than does glycemic control.

•   Secondary: BP control; lipid control; smoking cessation.

•   Tertiary: Glycemic control (Although glycemic control is strongly correlated with microvascular compli­cations, its impact on cardiometabolic risk is relatively small, compared to the risk conferred by hyper­tension, dyslipidemia, and smoking.)

Coming in June …  Motivating and Empowering Patients in the Self-Management of Diabetes.

Race, Sex, and Cardiometabolic Risk

Interview with:

Robert Eckel, MD, Professor of Medicine and Charles A. Boettcher II Chair in Atherosclerosis, University of Colorado Health Sciences Center, Denver, CO

Women

HDL-cholesterol: In premenopausal women, levels are generally higher than in men, contributing to lower risk for CVD.

Hypertension: Somewhat lower prevalence, compared to men.

Diabetes: Women with diabetes have the same risk for CVD as do men with diabetes (ie, the “gender benefit” seems to disappear).

Obesity: Most data suggest that central (ie, visceral) obesity confers greater risk for CVD than does lower-body obesity. Women are more likely than men to exhibit lower-body obesity (ie, “pear shape”). However, when women increase body fat, their levels of C-reactive protein (CRP) seem to increase more dramatically than in men with increasing body fat. This relationship and its implications are under investigation.

Role of estrogen: The lower risk for CVD in premenopausal women has been attributed to estrogen, but the relationship may be more complex. Before puberty, girls and boys have similar levels of HDL-cho­lesterol, but those levels decrease after puberty (with the onset of increased androgen production) in boys. After menopause, not only do estrogen levels decrease, but the relative concentration of andro­gens increases.

Race/ethnicity

Hypertension: Higher prevalence among blacks.

HDL-cholesterol: Latinos tend to have lower levels than whites, who tend to have somewhat lower levels than blacks.

Management: In general, targets (eg, BP, lipids, blood glucose) are the same, regardless of race/ethnicity.

Hypertension: Diagnosis and Management

Interview with:

Sheila Garris, MD, Clinical Hypertension Specialist and Associate Professor of Clinical Internal Medicine, Eastern Virginia Medical School, Norfolk, VA

Measuring BP

•   BP should be measured twice, taken ³5 min apart.

•   Patients should avoid eating or drinking for ³30 min before measuring BP.

•   Patients should be in a sitting position with both feet flat on the floor.

•   »80% of the upper arm must be covered by the bladder of the BP cuff. If the cuff is too small, the BP reading will be artificially high (potentially leading to inappropriate treatment).

•   The patient’s arm should be approximately at the level of the heart.

•   Before diagnosing a patient with hypertension, measure the BP in both arms.

Treatment approach: patients without diabetes

•   First-line therapy: thiazide diuretic (in most patients)

•   Two agents are recommended for patients with BP ³160/100 mm Hg. If the first agent is a drug that affects actual blood volume (eg, a diuretic) or relative blood volume (eg, a vasodilator), then the second agent should be a drug that affects the renin-angiotension-aldosterone system (eg, an angiotension-con­verting enzyme [ACE] inhibitor or angiotension-II receptor blocker [ARB]).

•   If BP remains high, up-titrate medications or add a third agent.

•   Consider secondary sources of hypertension — the most common being use of nonsteroidal anti-inflam­matory drugs (NSAIDs). Other common causes of secondary hypertension are sleep apnea and idiopathic hyperaldosteronism (IHA).

•   To work up a patient for IHA, order an aldosterone-to-renin ratio or refer to a clinical hypertension spe­cialist.

Note: Initiating a low-sodium diet can reduce systolic BP by 6 to 8 mm Hg (similar effect as a diuretic).

Complete guidelines for the management of hypertension are available in the 7th Report of the Joint Na­tional Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7).

Individualizing treatment

Patients with diabetes: Thiazide diuretics may worsen glycemic control. Therefore, a better first choice is an ACE inhibitor or ARB. If a second agent must be added, consider a calcium-channel blocker.

Women of childbearing age: ACE inhibitors and ARBs are associated with fetal abnormalities. Therefore, women taking these agents must be protected from pregnancy. Although oral contraceptives (OCs) may in­crease BP, they may be used as long as the BP is adequately controlled. Some antihypertensive agents (eg, va­sodilating b-blockers [eg, labetalol], methyldopa) are safe for women who are planning pregnancies.

Action for Health in
Diabetes (Look AHEAD) Trial

Show Me the Data!

Interview with:

Jeffrey Curtis, MD, Coinvestigator, Action for Health in Diabetes (Look AHEAD) Trial; National Institute of Dia­betes and Digestive and Kidney Diseases (NIDDK), Phoenix, AZ

Results from baseline
stress testing

•   Patients reported no symptoms
of CVD.

•   22.5% of tests showed
abnormal results.

•   12% of participants were unable to achieve ³5 METs.

•   ST segment depression was seen in 7.6%.

•   0.5% of participants demonstrated abnormal recovery of heart rate.

•   Angina occurred in 1.1%.

•   Detectable arrhythmia occurred in 0.71%.

•   The variable that best predicted abnormal results was age.

Conclusions

Overweight or obese adults with type 2 diabetes have 22% likelihood of having abnormal results on stress tests. Although it is not yet known whether these abnormalities will prove clinically significant, they have been associated with increased cardiovascular mortality in other studies. The authors do not broadly rec­ommend stress testing for all overweight patients with diabetes, but they note that clinicians should be mindful that even asymptomatic patients may be at increased risk for cardiovascular events, especially with increasing age.

Cardiometabolic Risk
in Patients with
Type 1 Diabetes

Interview with:

Trevor Orchard, MBBCh, MMedSci, FAHA, Professor of Epidemiology, Pediatrics, and Medicine, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA

Predictors of risk

Data from the Pittsburgh Epidemiology of Diabetes Complications Study shows that cardiovascular autonomic neuropathy (CAN) is a predictor of future development of arterial stiffness. Other predictors were smoking sta­tus and level of HDL cholesterol.

Measurements

Cardiac autonomic nerve function: Heart rate variability (R-R interval) during deep breathing, expressed as the expiration-to-inspiration (E/I) ratio.

Arterial stiffness: Pulse wave analysis was measured using a SphygmoCor Px system. Pulse pressure is another useful measure, but data by Prince and colleagues show that augmentation pressure and subendocardial viabil­ity ratio (SEVR) are somewhat better predictors.

Reducing cardiometabolic risk

Pharmacogenetics: Risk for CVD is reduced with vitamin E therapy in individuals with type 2 diabetes who have the haptoglobin 2-2 genotype. Emerging data also suggest a relationship between haptoglobin genotype and risk for CVD in patients with type 1 diabetes.

Management of standard risk factors: It is very important to control BP and lipids. For example, statin therapy should be considered for all patients with type 1 diabetes who are >30 yr of age. Risk assessment — Individu­als with type 1 diabetes should be evaluated for cardiometabolic risk on a regular basis, beginning at puberty. Targets — smoking cessation; LDL cholesterol <100 mg/dL; BP £120/80 mm Hg **.

** Note, the above recommendations are based on expert opinion and extrapolations from data in type 2 diabetes.

“Our data suggest that [risk for CVD in individuals with type 1 diabetes] is strongly related to renal disease. How­ever, we’ve seen a nice decline in renal disease and not as big a decline in CVD. That partly reflects the fact that we’ve been too focused on renal disease and not on cardiovascular risk.”

Articles Featured in the June Issue of Diabetes Care

Abbott CA: Explanations for the lower rates of diabetic neuropathy in Indian Asians versus Europeans

The Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group: The cost-effectiveness of continuous glucose monitoring in type 1 diabetes

Knip M: Prediction of Type 1 Diabetes in the General Population

Redmon JB: Effect of the Look AHEAD Study Intervention on medication use and related cost to treat cardio­vascular disease risk factors in individuals with type 2 diabetes

Rosenstock J: Effects of exenatide and lifestyle modification on body weight and glucose tolerance in obese subjects with and without prediabetes

Sawada SS: Long-term trends in cardiorespiratory fitness and the incidence of type 2 diabetes

Suggested Reading

Abbott CA: Explanations for the lower rates of diabetic neuropathy in Indian Asians versus Europeans; American Diabetes Association: Standards of medical care in diabetes – 2010. Diabetes Care 33 (Suppl 1):S11, 2010; Asleh R et al: Correction of HDL dysfunction in indi­viduals with diabetes and the haptoglobin 2-2 genotype. Diabetes 57:2794, 2008; Blonde L: Current antihyperglycemic treatment guidelines and algorithms for patients with type 2 diabetes mellitus. Am J Med 123 (3 Suppl):S12, 2010; Blum S et al: The effect of vitamin E supple­mentation on cardiovascular risk in diabetic individuals with different haptoglobin phenotypes. Atherosclerosis Feb 21, 2010 [Epub ahead of print]; Cignarella A et al: Emerging role of estrogen in the control of cardiometabolic disease. Trends Pharmacol Sci 31:183, 2010; Curtis JM et al: Prevalence and predictors of abnormal cardiovascular responses to exercise testing among persons with type 2 diabetes. The Look AHEAD Study. Diabetes Care 33:901, 2010; Danaei G et al: The promise of prevention: the effects of four preventable risk factors on na­tional life expectancy and life expectancy disparities by race and county in the United States. PLoS Med 7:e1000248, 2010; Homko CJ et al: Gender differences in cardiovascular risk factors and risk perception among individuals with diabetes. Diabetes Educ Apr 1, 2010 [Epub ahead of print]; Patel MR et al: Low diagnostic yield of elective coronary angiography. N Engl J Med 362:886, 2010; The Juvenile Diabe­tes Research Foundation Continuous Glucose Monitoring Study Group: The cost-effectiveness of continuous glucose monitoring in type 1 diabetes; Knip M: Prediction of Type 1 Diabetes in the General Population; Persell SD et al: Medication reconciliation and hyperten­sion control. Am J Med 123:182, 2010; Poulsen MK et al: Identification of asymptomatic type 2 diabetes mellitus patients with a low, inter­mediate, and high risk of ischaemic heart disease: Is there an algorithm? Diabetologia 53:659, 2020; Prince CT et al: Cardiovascular autonomic neuropathy, HDL cholesterol, and smoking correlate with arterial stiffness markers determined 18 years later in type 1 diabetes. Diabetes Care 33:652, 2010; Redmon JB: Effect of the Look AHEAD Study Intervention on medication use and related cost to treat cardio­vascular disease risk factors in individuals with type 2 diabetes; Rosenstock J: Effects of exenatide and lifestyle modification on body weight and glucose tolerance in obese subjects with and without prediabetes; Shivu GN et al: Relationship between coronary microvascular dys­function and cardiac energetics impairment in type 1 diabetes mellitus. Circulation 121:1209, 2010; Sawada SS: Long-term trends in cardio­respiratory fitness and the incidence of type 2 diabetes; The Look AHEAD Research Group: Reduction in weight and cardiovascular disease risk factors in individuals with type 2 diabetes. Diabetes Care 30:1374, 2007.

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Estimated time to complete the educational process:

Review Educational Objectives on page          1 5 minutes

Take pretest   10 minutes

Listen to audio program   60 minutes

Review written summary and suggested readings   35 minutes

Take posttest   10 minutes