How to Treat Hypertension in Type 2 Diabetes

A 68-year-old African American man presents for a checkup. He has had type 2 diabetes mellitus for the past 5 years but has no nephropathy and no history of cardiovascular disease. He is currently taking atorvastatin, 80 mg/d, and his low-density lipoprotein cholesterol level is 80 mg/dL. His blood pressure was 148/98 mm Hg at the last visit and is now 150/98 mm Hg. What is the best treatment for him?

BACKGROUND

In patients with type 2 diabetes mellitus, insulin resistance may cause hypertension by increasing sympathetic activity, renal reabsorption of sodium, or vascular tone. Uncontrolled hypertension is a major cardiovascular risk factor that also accelerates the progression of diabetic nephropathy.¹

EVIDENCE REVIEW

Blood pressure monitoring. Both the 2009 Standards of Medical Care in Diabetes published by the American Diabetes Association (ADA)² and the Seventh Report of the Joint National Committee (JNC 7)³ recommend regular monitoring of blood pressure (Table). The ADA recommends monitoring blood pressure at every visit, while the JNC does not recommend monitoring this frequently, specifically for patients with diabetes. The results of the United Kingdom Prospective Diabetes Study (UKPDS) suggest that blood pressure control may be more important than glycemic control for prevention of adverse cardiovascular outcomes.⁴ Therefore, checking blood pressure at every visit may be prudent.

Lifestyle modification. The ADA recommends 3 months of lifestyle modifications for patients with diabetes who have mildly elevated blood pressures.² The JNC recommends up to 6 months of lifestyle modifications for these patients.³ Lifestyle modifications consist of weight control, tobacco cessation, aerobic exercise, and dietary changes to decrease sodium and increase potassium and calcium intake.

Pharmacological therapy. Blood pressure lowering in patients with type 2 diabetes can be achieved with all classes of antihypertensives. The angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) can slow the progression of diabetic nephropathy and reduce microalbuminuria. Thiazide diuretics are good secondline agents for patients with normal renal function because they work synergistically with ACE inhibitors and ARBs. However, thiazides may adversely affect glycemic control. Loop diuretics should be used for patients with impaired renal function (glomerular filtration rate [GFR] of less than 30 mL/min). Based on the results of the Avoiding Cardiovascular Events Through Combination Therapy in Patients Living With Systolic Hypertension (ACCOMPLISH) trial,⁵ a long-acting dihydropyridine calcium channel blocker (CCB) may be considered as a second-line agent as well; however, the ADA recommends a diuretic.² If not used as a second-line medication, the longacting dihydropyridine CCB should be a third-line agent.

Follow-up. Patients with diabetes who are being treated for hypertension should be seen at least monthly until their blood pressure is controlled (less than 130/80 mm Hg) and more frequently as needed. After control is achieved, less frequent visits-every 3 to 6 months-are reasonable. Check renal function (blood urea nitrogen and creatinine levels and estimated GFR) and potassium levels about 2 weeks after an ACE inhibitor or ARB is started and periodically thereafter. Patients with renal artery stenosis may have an acute worsening of their renal function after starting an ACE inhibitor or ARB.

OTHER GUIDELINE RECOMMENDATIONS

The Institute for Clinical Systems Improvement. When hypertension is identified, it should be aggressively treated. For patients with type 2 diabetes, the systolic blood pressure goal is less than 130 mm Hg and the diastolic blood pressure goal is less than 80 mm Hg.¹

ACE inhibitors and ARBs are preferred first-line therapy. The possible advantages to ACE inhibitors include renal protection, decreased insulin resistance, lack of adverse effect on lipid profile, and cardiovascular risk reduction. Thiazide diuretics used to treat hypertension can reduce cardiovascular events, especially heart failure, in patients with type 2 diabetes.

Kaiser Permanente. Initiate antihypertensive therapy in patients with diabetes who have a systolic blood pressure of 140 mm Hg or higher and/or a diastolic blood pressure of 85 to 90 mm Hg or higher. After 3 months of lifestyle therapy, if systolic blood pressure is 130 to 139 mm Hg or diastolic blood pressure is 80 to 89 mm Hg, initiate drug therapy. When blood pressure is more than 20/10 mm Hg to 30/10 mm Hg above goal, starting therapy with 2 drugs, either as separate prescriptions or in fixed-dose combination, is recommended.⁶

For the treatment of diabetes and hypertension in the absence of heart failure, known coronary heart disease, or microalbuminuria, either a thiazide-type diuretic or an ACE inhibitor is the preferred first-line drug. The combination of hydrochlorothiazide/ACE inhibitor as first-line therapy is an option. When a second drug is required to control hypertension, it should be either an ACE inhibitor or a diuretic. If blood pressure is not controlled with a thiazide-type diuretic in addition to an ACE inhibitor, then treatment with a thiazide-type diuretic, an ACE inhibitor, and a β-blocker is recommended. For patients with diabetes and hypertension, the target blood pressure should be 130/80 mm Hg or lower.

OUTCOME OF THE CLINICAL CASE

Let's return to the 68-year-old patient with type 2 diabetes. His diagnosis is stage 2 hypertension because he is more that 20/10 mm Hg away from his goal (130/80 mm Hg).

After the results of a laboratory evaluation for secondary hypertension were normal, he began lifestyle changes and lisinopril, 20 mg/d. After 3 months of treatment, his blood pressure continued to be over goal at 142/92 mm Hg, but his renal function and potassium level were normal. At this point, his regimen was changed to a combination of lisinopril, 20 mg/d, with hydrochlorothiazide, 12.5 mg/d, and he was encouraged to continue his lifestyle changes. At follow-up 1 month later, his blood pressure was 128/78 mm Hg and he was tolerating his medication well. He is scheduled for a follow-up visit in 3 months.

References:

REFERENCES:

1.

Institute for Clinical Systems Improvement (ICSI).

Diagnosis and Management of Type 2 Diabetes Mellitus in Adults

. Bloomington, MN: Institute for Clinical Systems Improvement (ICSI); 2008:1-89.

2.

American Diabetes Association. Executive summary: standards of medical care in diabetes-2009 [published correction appears in

Diabetes Care

. 2009;32:754].

Diabetes Care

. 2009;32(suppl 1): S6-S12.

3.

Chobanian AV, Bakris GL, Black HR, et al; Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. National Heart, Lung, and Blood Institute; National High Blood Pressure Education Program Coordinating Committee. Seventh report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.

Hypertension

. 2003;42:1206-1252.

4.

UK Prospective Diabetes Study Group. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes; UKPDS 38 [published correction appears in

BMJ

. 1999;318:29].

BMJ

. 1998;317:703-713.

5.

Jamerson K, Weber MA, Bakris GL, et al; ACCOMPLISH Trial Investigators. Benazepril plus amlodipine or hydrochlorothiazide for hypertension in high-risk patients.

N Engl J Med

. 2008;359:2417-2428.

6.

Kaiser Permanente Care Management Institute.

Adult Diabetes Clinical Practice Guidelines

. Oakland, CA: Kaiser Permanente Care Management Institute; 2005:1-206.

7.

Ebell MH, Siwek J, Weiss BD, et al. Strength of recommendation taxonomy (SORT): a patientcentered approach to grading evidence in the medical literature.

Am Fam Physician

. 2004;69:549-557.

The opinions and assertions contained herein are the private views of the author and should not be construed as official or as reflecting the views of the Department of the Navy or the Department of Defense.