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The Management of Hypertension (Clinical Evaluation)

September 12, 2015 Cardiology, Diabetes, Infectious Diseases, Pharmacotherapy, Therapeutics No comments , , , , , , , ,

Frequently, the only sign of essential hypertension is elevated BP. The rest of the physical examination may be completely normal. However, a complete medical evaluation including a comprehensive medical history, physical examination, and laboratory and/or diagnostic test is recommended after diagnosis to identify secondary causes, identify other CV risk factors or comorbid conditions that may define prognosis and/or guide therapy, and assess for the presence of absence of hypertension-associated target-organ damage.

For the patients who have been diagnosed with hypertension, we should ask a few questions that are necessary to make a clinical evaluation for these patients. Here is an example of a patient with hypertension.

D.C. is a 44-year-old black man who presents to his primary care provider concerned about high BP. At an employee health screening last month he was told he has stage 1 hypertension. His medical history is significant for allergic rhinitis. His BP was 144/84 and 146/86 mm Hg last year during an employee health screening at work. D.C.’s father had hypertension and died of an MI at age 54. His mother had diabetes and hypertension and died of a stroke at age 68. D.C. smokes on pack per day of cigarettes and thinks his BP is high because of job-related stress. He does not engage in any regular exercise and does not restrict his diet in any way, although he knows he should lose weight.

Physical examination show he is 175 cm tall, weighs 108 kg (BMI, 35.2 kg/m2), BP is 148/88 mm Hg (left arm) and 146/86 mm Hg (right arm) while sitting, heart rate is 80 beats/minute. Six months ago, his BP values were 152/88 mm Hg and 150/84 mm Hg when he was seen by his primary-care provider for allergic rhinitis. Funduscopic examination reveals mild arterial narrowing and arteriovenous nicking, with no exudates or hemorrhages. The other physical examination findings are essentially normal.

D.C.’s fasting laboratory serum values are as follows:

Blood urea nitrogen, 24 mg/dL

Creatinine, 1.0 mg/dL

Glucose, 105 mg/dL (Fasting?)

Potassium, 4.4 mEq/L

Uric acid, 6.5 mg/dL

Total cholesterol, 196 mg/dL

Low-density lipoprotein cholesterol, 141 mg/dL

High-density lipoprotein cholesterol, 32 mg/dL

Triglycerides, 170 mg/dL

An electrocardiogram is normal except for left ventricular hypertrophy.

PS: Normal values are marked in green and abnormal values are marked in orange.


Clinical Presentation

Question 1 What is the clinical presentation D.C.?

All the information above could be the part of D.C.’s clinical presentation. Besides, we could classify the stage of D.C.’s hypertension as shown below.

D.C. has uncontrolled stage 1 hypertension. He has had elevated BP values, measured in clinical environments, and meets the diagnostic criteria for hypertension because two or more of his BP measurements are elevated on separate days. SBP values are consistently stage 1, whereas DBP values are all in the prehypertension range. The higher of the two classifications is used to classify hypertension.

Question 2 Why does D.C. have hypertension?

D.C. has essential hypertension; therefore, the exact cause is not known. He has several characteristics (e.g., family history of hypertension, obesity) that may have increased his chance of developing hypertension. Race and sex also influence the prevalence of hypertension Across all age groups, black have a higher prevalence of hypertension than do whites and Hispanics. Similar to other form of CV disease, hypertension is more server, more like to include hypertension-associated complications, and occurs at an earlier age in black patients.


Patient Evaluation and Risk Assessment

The presence of absence of hypertension-associated complications as well as other major CV risk factors (Table 14-5) must be assessed in D.C. Also, secondary cause of hypertension (Table 14-3), if suggested by history and clinical examination findings, should be identified and managed accordingly. The presence of concomitant medical conditions (e.g., diabetes) should be assessed, and lifestyle habits should be evaluated so that they can be used to guide therapy.

  • Hypertension-associated complications
  • Secondary causes of hypertension
  • Concomitant medical conditions

Question 3 Dose D.C. has secondary cause of hypertension?

The most common secondary causes of hypertension are list in Table 3-1. Patients with secondary hypertension might have signs or symptoms suggestive of the underlying disorders.

Table 3-1 Secondary Causes of Hypertension.

  • Patients with pheochromocytoma may have a history of paroxysmal headaches, sweating, tachycardia, and palpitations. Over half of these patients suffer from episodes of orthostatic hypotension.
  • In primary hyperaldosteronism symptoms related to hypokalemia usually include muscle cramps and muscle weakness.
  • Patients with Cushing’s syndrome may complain of weight gain, polyuria, edema, menstrual irregularities, recurrent acne, or muscle weakness and have several classic physical features (e.g., moon face, buffalo hump, hirsutism).
  • Patient with coarctation of the aorta may have higher BP in the arms than in legs and diminished or even absent femoral pulses.
  • Patient with renal artery stenosis may have an abdominal systolic-diastolic bruit.

Also, routine laboratory tests may also help identify secondary hypertension. For example, Baseline hypokalemia may suggest mineralocorticoid-induced hypertension. Protein, red blood cells, and casts in the urine may indicate renovascular disease. Some laboratory tests are used specifically to diagnose secondary hypertension. These include plasma norepinephrine and urinary metanephrine for pheochromocytoma, plasma and urinary aldosterone concentrations for primary hyperaldosteronism, and plasma rennin activity, captopril stimulation test, renal vein renin, and renal artery angiography for renoascular disease.

Certain drugs and other products can result in drug-induced hypertension. For some patients, the addition of these agents can be the cause of elevated BP or can exacerbate underlying hypertension. Identify a temporal relationship between starting the suspected agent and developing elevated BP is most suggestive of drug-induced BP elevation.

Question 4 Which hypertension-associated complications are present in D.C.?

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A complete physical examination to evaluate hypertension-associated complications includes examination of the optic funds; auscultation for carotid, abdominal, and femoral bruits; palpation of the thyroid gland; heart and lung examination; abdominal examination for enlarged kidney, masses, and abnormal aortic pulsation; lower extremity palpation for edema and pulses; and neurologic assessment. Routine laboratory assessment after diagnosis should include the following: EKG; urinalysis; fasting glucose; hematocrit; serum potassium, creatinine, and calcium; and fasting lipid panel. Optional testing may include measurement of urinary albumin excretion or albumin-to-creatinine ratio, or additional tests specific for secondary causes if suspected.

Question 5 What other forms of hypertension-associated complications is D.C. at risk for?

Hypertension adversely affects many organ systems, including the heart, brain, kidneys, peripheral circulation, and eyes (Table 14-5). Damage to these systems resulting from hypertension is termed hypertension-associated complications, target-organ damage, or CV disease. There are often misconceptions about the term CV disease and CAD. CV disease encompasses the broad scope of all forms of hypertension-associated complications. CAD is simply a subset of CV disease and refers specifically to disease related to the coronary vasculature, including ischemic heart disease and MI.

Hypertension can affect the heart either indirectly, by promoting atherosclerotic changes, or directly, via pressure-related effects. Hypertension can promote CV disease and increase the risk for ischemic events, such as angina and MI. Antihypertensive therapy has been shown to reduce the risk of these coronary events. Hypertension also promotes the development of LVH, which is a myocardial (cellular) change, not an arterial change. These two conditions often coexist, however. It is commonly believed that LVH is a compensatory mechanism of the heart in response to the increased resistance caused by elevated BP (more accurately, the afterload). Recall the definition of afterload, that is, wall tension=(pressure * radius)/(wall thickness). LVH is a strong and independent risk factor for CAD, left ventricular dysfunction, and arrhythmia. LVH does not indicate the presence of left ventricular dysfunction, but is a risk for progression to left ventricular dysfunction, which is considered a hypertension-associated complication. This may be caused by ischemia, excessive LVH, or pressure overload. Ultimately, left ventricular dysfunction results in a decrease ability to contract (systolic dysfunction).

Hypertension is one of the most frequent causes of cerebrovascular disease. Cerebrovascular signs can manifest as transient ischemic attacks, ischemic strokes, multiple cerebral infarcts, and hemorrhages. Residual functional deficits caused by stroke are among the most devastating forms of hypertension-associated complications. Clinical trials have demonstrated that antihypertensive therapy can significantly reduce the risk of both initial and recurrent stroke. A sudden, prolonged increase in BP also can cause hypertensive encephalopathy, which is classified as a hypertensive emergency.

The GFR is used to estimate kidney function, which declines with aging. This rate of decline is greatly accelerated by hypertension. Hypertension is associated with nephrosclerosis, which is caused by increased intraglomerular pressure. It is unknown whether a primary kidney lesion with ischemia causes systemic hypertension or whether systemic hypertension directly causes glomerular capillary damage by increasing intraglomerular pressure. Regardless, CKD, whether mild or severe, can progress to kidney failure (stage 5 CKD) and the need for dialysis. Studies have demonstrated that controlling hypertension is the most important strategy to slow the rate of kidney function decline, but it may not be entirely effective in slowing the progression of renal impairment in all patients.

In hypertension, stage 3 CKD or worse is considered a hypertension-associated complication (GFR values of <60 mL/min/1.73 m2). An estimated GFR of less than 60 mL/min/1.73 m2 corresponds approximately to a serum concentration of greater than 1.5 mg/dL in an average man and greater than 1.3 mg/dL in an average woman. This level of kidney compromise lowers an individual’s BP goal to less than 130/80 mm Hg according to multiple guidelines. The presence of persistent albuminuria (>300 mg albumin in a 24-hour urine collection or 200 mg albumin/g creatinine on a spot urine measurement) also indicates significant CKD, for which achieving the more aggressive BP goal is a strategy to minimize the rate of progression to kidney failure.

Peripheral arterial disease, a non coronary form of atherosclerotic vascular disease, is considered a hypertension-associated complication. It is equivalent in CV risk to CHD. Risk factor reduction, BP control, and anti platelet agent(s) are needed to decrease progression. Complications of peripheral arterial disease can include infection and necrosis, which in some cases require revascularization procedures or extremity amputation.

Hypertension causes retinopathies that can progress to blindness. Retinopathy is evaluated according to the Keith, Wagener, and Barker funduscopic classification system. Grade 1 is characterized by narrowing of the arterial diameter, indicating vasoconstriction. Arteriovenous nicking is the hallmark of grade 2, indicating atherosclerosis. Longstanding, untreated hypertension can cause cotton wool exudates and flame hemorrhages (grade 3). In severe cases, papilledema occurs, and this is classified as grade 4.

Question 6 Which major CV risk factors are present in D.C.?

As shown in Table 14-5, major CV risk factors include advanced age (>55 years for men, >65 years for women), cigarette smoking, diabetes mellitus, dyslipidemia, family history of premature atherosclerotic vascular disease (men <55 years or women <65 years) in primary relatives, hypertension, kidney disease (microablubuminuria or estimated GFR <60 mL/min/1.73 m2), obesity (BMI >=30 kg/m2), and physical inactivity.

PS: Estimated GFR calculated from online calculator for D.C. is 105 mL/min/1.73 m(online calculator: http://www.davita.com/gfr-calculator/).

So according to D.C.’s clinical presentation, he has major CV risk factors that are marked in orange, that is, 5 factors in total, including the essential hypertension.

Question 7 What is D.C.’s BP goal and how can Framingham risk scoring influence BP goal determination?

D.C. is a primary prevention patient because he does not yet have any hypertension-associated compilations (or compelling indications). He has multiple CV risk factors, so controlling his BP is of paramount importance to reduce the risk of developing hypertension-associated complications. The JNC-8 guidelines recommend the initial BP goal for hypertension patients with age of <60 years should be 140/90 mm Hg, which has grade A evidence (strong recommendation) for patients from 30 through 59 years of age, and grade E (expert opinion) for those from 18 through 29 years of age. So D.C.’s initial BP goal should be below 140/90 mm Hg.

The framingham risk scoring system is available as an online calculator at NIH site of http://cvdrisk.nhlbi.nih.gov/calculator.asp. According to D.C.’s clinical presentation, he will has a CV risk of  14% in a next 10-year period of expectation before we intervention, which means in a population cohort such as D.C., 14 in 100 individuals will develop CV diseases after a period of 10-year, if we don’t treat these CV risk factors (if these risk factors worsen, the incidence of developing CV diseases would be higher). If we treat D.C.’s current hypertension target the BP goal, with other interventions that target D.C.’s rest risk factors like habit of smoking, etc., the incidence of developing CV diseases would be attenuated (In D.C.’s example, the incidence would decrease to 5%, that is 5 in 100 of individuals will develop CV diseases in a period of 10-year). Compare the results without/with interventions to D.C.

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The intervention above does not include the management of dyslipidemia. According to the latest AHA guideline, four types of patients need the intervention for dyslipidemia, including: 1.secondary prevention in individuals with clinical ASCVD; 2. primary prevention in individuals with primary elevations of LDL-C >=190 mg/dL; 3.primary prevention in individuals with diabetes 40 to 75 years of age who have LDL-C 70 to 189 mg/dL; and 4.primary prevention in individual without diabetes and with estimated 10-year ASCVD risk>=7.5%, 40 to 75 years of age who have LDL-C 70 to 189 mg/dL. (References: http://www.tomhsiung.com/wordpress/2014/07/the-management-of-dyslipidemia/). So we need to calculate D.C.’s ASCVD risk from another tool developed by ACC/AHA (American College of Cardiology/American Heart Association), which is available as iOs apps. So the result of ASCVD risk of D.C. is 9.7% (>=7.5%) without any intervention, whereas ASCVD risk is 8.6% (still >=7.5%) with interventions of antihypertensive therapy and smoke cessation. Therefore, the dyslipidemia should be treated for D.C.

PS: ASCVD includes coronary heart disease (CHD), stroke, and peripheral arterial disease, all of presumed atherosclerotic origin.

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Testing for diabetes in asymptomatic patients

May 13, 2012 Diabetes No comments , ,

In last post we talked about the categories of increased risk for diabetes (prediabetes).

Now we will talk about how to identify the people at risk for diabetes.

For many illnesses, there is a major distinction between screening and diagnostic testing. However, for diabetes, the same tests would be used for “screening” as for diagnosis.

Why the screening for diabetes is significant. Because diabetes may be identified anywhere along a spectrum of clinical scenarios ranging from a seemingly low-risk individual who happens to have glucose testing, to a higher-risk individual whom the provider tests because of high suspicion of diabetes, to the symptomatic patient.

Here in this post we primarily discuss the testing for diabetes in those without symptoms. The same assays used for testing for diabetes will also detect individuals with prediabetes.

Prediabetes and diabetes meet established criteria for conditions in which early detection is appropriate. Both conditions are common, increasing in prevalence, and impose significant public health burdens. There is a long presymptomatic phase before the diagnosis of type 2 diabetes is usually made. Relatively simple tests are available to detect preclinical disease. Additionally, the duration of glycemic burden is a strong predictor of adverse outcomes, and effective interventions exist to prevent progression of prediabetes to diabetes (see section IV. PREVENTION/DELAY OF TYPE 2 DIABETES) and to reduce risk of complications of diabetes (see section V.I. PREVENTION AND MANAGEMENT OF DIABETES COMPLICATIONS).

Type 2 diabetes is frequently not diagnosed until complications appear, and approximately one-fourth of all people with diabetes in the U.S. may be undiagnosed. The effectiveness of early identification of prediabetes and diabetes through mass testing of asymptomatic individuals has not been proven definitively, and rigorous trials to provide such proof are unlikely to occur. In a large randomized controlled trial (RCT) in Europe, general practice patients between the ages of 40 and 69 years were screened for diabetes and then randomized by practice to routine care of diabetes or intensive treatment of multiple risk factors. After 5.3 years of follow-up, CVD risk factors were modestly but significantly more improved with intensive treatment. Incidence of first CVD event and mortality rates were not significantly different between groups (16). This study would seem to add support for early treatment of screen-detected diabetes, as risk factor control was excellent even in the routine treatment arm and both groups had lower event rates than predicted. The absence of a control unscreened arm limits the ability to definitely prove that screening impacts outcomes. Mathematical modeling studies suggest that screening independent of risk factors beginning at age 30 or age 45 years is highly cost-effective (<$11,000 per quality-adjusted life-year gained) (17).

Recommendations for testing for diabetes in asymptomatic, undiagnosed adults are listed in Table 4. Testing should be considered in adults of any age with BMI ≥25 kg/m2 and one or more of the known risk factors for diabetes. There is compelling evidence that lower BMI cut points suggest diabetes risk in some racial and ethnic groups. In a large multiethnic cohort study, for an equivalent incidence rate of diabetes conferred by a BMI of 30 kg/m2 in whites, the BMI cutoff value was 24 kg/m2 in South Asians, 25 kg/m2 in Chinese, and 26 kg/m2 African Americans (18).Disparities in screening rates, not explainable by insurance status, are highlighted by evidence that despite much higher prevalence of type 2 diabetes, non-Caucasians in an insured population are no more likely than Caucasians to be screened for diabetes (19). Because age is a major risk factor for diabetes, testing of those without other risk factors should begin no later than age 45 years.

Either A1C, FPG, or the 2-h OGTT is appropriate for testing. It should be noted that the tests do not necessarily detect diabetes in the same individuals. The efficacy of interventions for primary prevention of type 2 diabetes (2026) has primarily been demonstrated among individuals with IGT, not for individuals with isolated IFG or for individuals with specific A1C levels.

The appropriate interval between tests is not known (27). The rationale for the 3-year interval is that false negatives will be repeated before substantial time elapses, and there is little likelihood that an individual will develop significant complications of diabetes within 3 years of a negative test result. In the modeling study, repeat screening every 3 or 5 years was cost-effective (17).

Because of the need for follow-up and discussion of abnormal results, testing should be carried out within the health care setting. Community screening outside a health care setting is not recommended because people with positive tests may not seek, or have access to, appropriate follow-up testing and care. Conversely, there may be failure to ensure appropriate repeat testing for individuals who test negative. Community screening may also be poorly targeted, i.e., it may fail to reach the groups most at risk and inappropriately test those at low risk (the worried well) or even those already diagnosed.

The recommendations are:

  • Testing to detect type 2 diabetes and assess risk for future diabetes in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI ≥25 kg/m2) and who have one or more additional risk factors for diabetes. In those without these risk factors, testing should begin at age 45 years.
  • If test are normal, repeat testing at least at 3-year intervals is resonable.
  • To test for diabetes or to assess risk of future diabetes, the A1C, FPG, or 2-h 75-g OGTT are appropriate.
  • In those identified with increased risk for future diabetes, identify and, if appropriate, treat other CVD risk factors.

Criterias for testing diabetes in asymptomatic adult individuals:

  • physical inactivity

  • first-degree relative with diabetes

  • high-risk race/ethnicity (e.g., African American, Latino, Native American, Asian American, Pacific Islander)

  • women who delivered a baby weighing >9 lb or who were diagnosed with GDM

  • hypertension (blood pressure ≥140/90 mmHg or on therapy for hypertension)

  • HDL cholesterol level <35 mg/dL (0.90 mmol/L) and/or a triglyceride level >250 mg/dL (2.82 mmol/L)

  • women with PCOS

  • A1C ≥5.7%, IGT, or IFG on previous testing

  • other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans)

  • history of CVD