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Clinical Case Study On Hypertension

Presentation

L.N. is a 49-year-old white woman with a history of type 2 diabetes, obesity, hypertension, and migraine headaches. The patient was diagnosed with type 2 diabetes 9 years ago when she presented with mild polyuria and polydipsia. L.N. is 5′4″ and has always been on the large side, with her weight fluctuating between 165 and 185 lb.

Initial treatment for her diabetes consisted of an oral sulfonylurea with the rapid addition of metformin. Her diabetes has been under fair control with a most recent hemoglobin A1c of 7.4%.

Hypertension was diagnosed 5 years ago when blood pressure (BP) measured in the office was noted to be consistently elevated in the range of 160/90 mmHg on three occasions. L.N. was initially treated with lisinopril, starting at 10 mg daily and increasing to 20 mg daily, yet her BP control has fluctuated.

One year ago, microalbuminuria was detected on an annual urine screen, with 1,943 mg/dl of microalbumin identified on a spot urine sample. L.N. comes into the office today for her usual follow-up visit for diabetes. Physical examination reveals an obese woman with a BP of 154/86 mmHg and a pulse of 78 bpm.

Questions

  1. What are the effects of controlling BP in people with diabetes?

  2. What is the target BP for patients with diabetes and hypertension?

  3. Which antihypertensive agents are recommended for patients with diabetes?

Commentary

Diabetes mellitus is a major risk factor for cardiovascular disease (CVD). Approximately two-thirds of people with diabetes die from complications of CVD. Nearly half of middle-aged people with diabetes have evidence of coronary artery disease (CAD), compared with only one-fourth of people without diabetes in similar populations.

Patients with diabetes are prone to a number of cardiovascular risk factors beyond hyperglycemia. These risk factors, including hypertension, dyslipidemia, and a sedentary lifestyle, are particularly prevalent among patients with diabetes. To reduce the mortality and morbidity from CVD among patients with diabetes, aggressive treatment of glycemic control as well as other cardiovascular risk factors must be initiated.

Studies that have compared antihypertensive treatment in patients with diabetes versus placebo have shown reduced cardiovascular events. The United Kingdom Prospective Diabetes Study (UKPDS), which followed patients with diabetes for an average of 8.5 years, found that patients with tight BP control (< 150/< 85 mmHg) versus less tight control (< 180/< 105 mmHg) had lower rates of myocardial infarction (MI), stroke, and peripheral vascular events. In the UKPDS, each 10-mmHg decrease in mean systolic BP was associated with a 12% reduction in risk for any complication related to diabetes, a 15% reduction for death related to diabetes, and an 11% reduction for MI. Another trial followed patients for 2 years and compared calcium-channel blockers and angiotensin-converting enzyme (ACE) inhibitors, with or without hydrochlorothiazide against placebo and found a significant reduction in acute MI, congestive heart failure, and sudden cardiac death in the intervention group compared to placebo.

The Hypertension Optimal Treatment (HOT) trial has shown that patients assigned to lower BP targets have improved outcomes. In the HOT trial, patients who achieved a diastolic BP of < 80 mmHg benefited the most in terms of reduction of cardiovascular events. Other epidemiological studies have shown that BPs > 120/70 mmHg are associated with increased cardiovascular morbidity and mortality in people with diabetes. The American Diabetes Association has recommended a target BP goal of < 130/80 mmHg. Studies have shown that there is no lower threshold value for BP and that the risk of morbidity and mortality will continue to decrease well into the normal range.

Many classes of drugs have been used in numerous trials to treat patients with hypertension. All classes of drugs have been shown to be superior to placebo in terms of reducing morbidity and mortality. Often, numerous agents (three or more) are needed to achieve specific target levels of BP. Use of almost any drug therapy to reduce hypertension in patients with diabetes has been shown to be effective in decreasing cardiovascular risk. Keeping in mind that numerous agents are often required to achieve the target level of BP control, recommending specific agents becomes a not-so-simple task. The literature continues to evolve, and individual patient conditions and preferences also must come into play.

While lowering BP by any means will help to reduce cardiovascular morbidity, there is evidence that may help guide the selection of an antihypertensive regimen. The UKPDS showed no significant differences in outcomes for treatment for hypertension using an ACE inhibitor or a β-blocker. In addition, both ACE inhibitors and angiotensin II receptor blockers (ARBs) have been shown to slow the development and progression of diabetic nephropathy. In the Heart Outcomes Prevention Evaluation (HOPE) trial, ACE inhibitors were found to have a favorable effect in reducing cardiovascular morbidity and mortality, whereas recent trials have shown a renal protective benefit from both ACE inhibitors and ARBs. ACE inhibitors and β-blockers seem to be better than dihydropyridine calcium-channel blockers to reduce MI and heart failure. However, trials using dihydropyridine calcium-channel blockers in combination with ACE inhibitors and β-blockers do not appear to show any increased morbidity or mortality in CVD, as has been implicated in the past for dihydropyridine calcium-channel blockers alone. Recently, the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) in high-risk hypertensive patients, including those with diabetes, demonstrated that chlorthalidone, a thiazide-type diuretic, was superior to an ACE inhibitor, lisinopril, in preventing one or more forms of CVD.

L.N. is a typical patient with obesity, diabetes, and hypertension. Her BP control can be improved. To achieve the target BP goal of < 130/80 mmHg, it may be necessary to maximize the dose of the ACE inhibitor and to add a second and perhaps even a third agent.

Diuretics have been shown to have synergistic effects with ACE inhibitors, and one could be added. Because L.N. has migraine headaches as well as diabetic nephropathy, it may be necessary to individualize her treatment. Adding a β-blocker to the ACE inhibitor will certainly help lower her BP and is associated with good evidence to reduce cardiovascular morbidity. The β-blocker may also help to reduce the burden caused by her migraine headaches. Because of the presence of microalbuminuria, the combination of ARBs and ACE inhibitors could also be considered to help reduce BP as well as retard the progression of diabetic nephropathy. Overall, more aggressive treatment to control L.N.'s hypertension will be necessary. Information obtained from recent trials and emerging new pharmacological agents now make it easier to achieve BP control targets.

Clinical Pearls

  1. Hypertension is a risk factor for cardiovascular complications of diabetes.

  2. Clinical trials demonstrate that drug therapy versus placebo will reduce cardiovascular events when treating patients with hypertension and diabetes.

  3. A target BP goal of < 130/80 mmHg is recommended.

  4. Pharmacological therapy needs to be individualized to fit patients' needs.

  5. ACE inhibitors, ARBs, diuretics, and β-blockers have all been documented to be effective pharmacological treatment.

  6. Combinations of drugs are often necessary to achieve target levels of BP control.

  7. ACE inhibitors and ARBs are agents best suited to retard progression of nephropathy.

Footnotes

  • Evan M. Benjamin, MD, FACP, is an assistant professor of medicine and Vice President of Healthcare Quality at Baystate Medical Center in Springfield, Mass.

  • American Diabetes Association

References

Ms. C is a 42-year-old black American woman with a 7-year history of hypertension first diagnosed during her last pregnancy. Her family history is positive for hypertension, with her mother dying at 56 years of age from hypertension-related cardiovascular disease (CVD). In addition, both her maternal and paternal grandparents had CVD.

At physician visit one, Ms. C presented with complaints of headache and general weakness. She reported that she has been taking many medications for her hypertension in the past, but stopped taking them because of the side effects. She could not recall the names of the medications. Currently she is taking 100 mg/day atenolol and 12.5 mg/day hydrochlorothiazide (HCTZ), which she admits to taking irregularly because “... they bother me, and I forget to renew my prescription.” Despite this antihypertensive regimen, her blood pressure remains elevated, ranging from 150 to 155/110 to 114 mm Hg. In addition, Ms. C admits that she has found it difficult to exercise, stop smoking, and change her eating habits. Findings from a complete history and physical assessment are unremarkable except for the presence of moderate obesity (5 ft 6 in., 150 lbs), minimal retinopathy, and a 25-year history of smoking approximately one pack of cigarettes per day. Initial laboratory data revealed serum sodium 138 mEq/L (135 to 147 mEq/L); potassium 3.4 mEq/L (3.5 to 5 mEq/L); blood urea nitrogen (BUN) 19 mg/dL (10 to 20 mg/dL); creatinine 0.9 mg/dL (0.35 to 0.93 mg/dL); calcium 9.8 mg/dL (8.8 to 10 mg/dL); total cholesterol 268 mg/dL (< 245 mg/dL); triglycerides 230 mg/dL (< 160 mg/dL); and fasting glucose 105 mg/dL (70 to 110 mg/dL). The patient refused a 24-h urine test.

Clinical Management and Treatment Decisions

Taking into account the past history of compliance irregularities and the need to take immediate action to lower this patient’s blood pressure, Ms. C’s pharmacologic regimen was changed to a trial of the angiotensin-converting enzyme (ACE) inhibitor enalapril, 5 mg/day; her HCTZ was discontinued. In addition, recommendations for smoking cessation, weight reduction, and diet modification were reviewed as recommended by the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI).1

After a 3-month trial of this treatment plan with escalation of the enalapril dose to 20 mg/day, the patient’s blood pressure remained uncontrolled. The patient’s medical status was reviewed, without notation of significant changes, and her antihypertensive therapy was modified. The ACE inhibitor was discontinued, and the patient was started on the angiotensin-II receptor blocker (ARB) losartan, 50 mg/day.

After 2 months of therapy with the ARB the patient experienced a modest, yet encouraging, reduction in blood pressure (140/100 mm Hg). Serum electrolyte laboratory values were within normal limits, and the physical assessment remained unchanged. The treatment plan was to continue the ARB and reevaluate the patient in 1 month. At that time, if blood pressure control remained marginal, low-dose HCTZ (12.5 mg/day) was to be added to the regimen.

Hypertension in Black Americans

Hypertension remains a significant health problem in the United States (US) despite recent advances in antihypertensive therapy. The role of hypertension as a risk factor for cardiovascular morbidity and mortality is well established.2–7 The age-adjusted prevalence of hypertension in non-Hispanic black Americans is approximately 40% higher than in non-Hispanic whites.8 Black Americans have an earlier onset of hypertension and greater incidence of stage 3 hypertension than whites, thereby raising the risk for hypertension-related target organ damage.1,8 For example, hypertensive black Americans have a 320% greater incidence of hypertension-related end-stage renal disease (ESRD), 80% higher stroke mortality rate, and 50% higher CVD mortality rate, compared with that of the general population.1,9 In addition, aging is associated with increases in the prevalence and severity of hypertension.8

Pharmacologic Treatment of Hypertension in Black Americans

Research findings suggest that risk factors for coronary heart disease (CHD) and stroke, particularly the role of blood pressure, may be different for black American and white individuals.10–12 Some studies indicate that effective treatment of hypertension in black Americans results in a decrease in the incidence of CVD to a level that is similar to that of nonblack American hypertensives.13,14

Data also reveal differences between black American and white individuals in responsiveness to antihypertensive therapy. For instance, studies have shown that diuretics15,16 and the calcium channel blocker diltiazem16,17 are effective in lowering blood pressure in black American patients, whereas β-adrenergic receptor blockers and ACE inhibitors appear less effective.15,16 In addition, recent studies indicate that ARB may also be effective in this patient population.

Angiotensin-II receptor blockers are a relatively new class of agents that are approved for the treatment of hypertension. Currently, four ARB have been approved by the US Food and Drug Administration (FDA): eprosartan, irbesartan, losartan, and valsartan. Recently, a 528-patient, 26-week study compared the efficacy of eprosartan (200 to 300 mg/twice daily) versus enalapril (5 to 20 mg/daily) in patients with essential hypertension (baseline sitting diastolic blood pressure [DBP] 95 to 114 mm Hg). After 3 to 5 weeks of placebo, patients were randomized to receive either eprosartan or enalapril. After 12 weeks of therapy within the titration phase, patients were supplemented with HCTZ as needed. In a prospectively defined subset analysis, black American patients in the eprosartan group (n = 21) achieved comparable reductions in DBP (−13.3 mm Hg with eprosartan; −12.4 mm Hg with enalapril) and greater reductions in systolic blood pressure (SBP) (−23.1 with eprosartan; −13.2 with enalapril), compared with black American patients in the enalapril group (n = 19) (Fig. 1).18 Additional trials enrolling more patients are clearly necessary, but this early experience with an ARB in black American patients is encouraging.

Efficacy of the angiotensin II receptor blocker eprosartan in black American with mild to moderate hypertension (baseline sitting DBP 95 to 114 mm Hg) in a 26-week study. Eprosartan, 200 to 300 mg twice daily (n = 21, solid bar), enalapril 5 to 20 mg daily (n = 19, diagonal bar). †10 of 21 eprosartan patients and seven of 19 enalapril patients also received HCTZ. Adapted from data in Levine: Subgroup analysis of black hypertensive patients treated with eprosartan or enalapril: results of a 26-week study, in Programs and abstracts from the 1st International Symposium on Angiotensin-II Antagonism, September 28–October 1, 1997, London, UK.

Approximately 30% of all deaths in hypertensive black American men and 20% of all deaths in hypertensive black American women are attributable to high blood pressure. Black Americans develop high blood pressure at an earlier age, and hypertension is more severe in every decade of life, compared with whites. As a result, black Americans have a 1.3 times greater rate of nonfatal stroke, a 1.8 times greater rate of fatal stroke, a 1.5 times greater rate of heart disease deaths, and a 5 times greater rate of ESRD when compared with whites.19 Therefore, there is a need for aggressive antihypertensive treatment in this group. Newer, better tolerated antihypertensive drugs, which have the advantages of fewer adverse effects combined with greater antihypertensive efficacy, may be of great benefit to this patient population.

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© 1998 by the American Journal of Hypertension, Ltd.

American Journal of Hypertension, Ltd.

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