SAN DIEGO – A 67-year-old woman with poorly controlled diabetes, diabetic retinopathy, and diabetic nephropathy visits your office for routine follow-up.
Her blood pressure is 165/95 mm Hg, her pulse is 71 beats per minute, her body mass index is 36 kg/m2, and labs reveal that her creatinine level is 1.2 mg/dL, her potassium level is 5.5 mmol/L, and she is spilling 3,500 mg of albuminuria in her urine, "which is quite significant," Dr. Kimberly Harper said at a meeting on primary care medicine sponsored by the Scripps Clinic.
This patient is also on insulin, lisinopril 20 mg/day, amlodipine 5 mg/day, and simvastatin 10 mg/day. How would you manage her hypertension? In the clinical opinion of Dr. Harper, a nephrologist at Scripps Clinic, La Jolla, Calif., the best approach would be to advise her to exercise, watch her sodium intake, and lose weight, as well as to increase her dose of lisinopril and add a thiazide diuretic to help control her potassium.
"As physicians managing hypertension, lifestyle modification is of the utmost importance," Dr. Harper said. "This is easier said than done, but if we can motivate our patients to do these things, we can help to get their blood pressure under better control without the side effects of medications."
According to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, for every 10 kg of weight loss, patients typically experience a 5-10 mm Hg reduction in systolic blood pressure, while keeping sodium intake to less than 2,400 mg/day can lead to a 2-8 mm Hg reduction. In addition, at least 30 minutes of aerobic exercise most days of the week can translate into a 4-9 mm Hg reduction, while moderate consumption of alcohol can mean a 2-4 mm Hg reduction. "This is defined as no more than one alcoholic beverage in a setting for women and no more than two alcoholic beverages in a setting for men," Dr. Harper said.
She makes it a point to inform patients on the risk of hyperkalemia, because over time diabetes can cause a type-4 renal tubular acidosis. In addition, all renin-angiotensin-aldosterone system medications can induce hyperkalemia. "I tell patients that hyperkalemia can lead to a fatal cardiac arrhythmia," Dr. Harper said. "Their ears tend to perk up when I say that."
She also instructs patients to follow a diet restricted to less than 2,000-3,000 mg potassium/day, depending on how high their potassium levels are.
In addition, Dr. Harper will often prescribe a thiazide or loop diuretic to help with the excretion of potassium.
She closed her presentation by highlighting experimental treatments for hypertension on the horizon. One is a hypertension vaccine that inhibits angiotensin II. A phase II trial of 24-hour blood pressure monitoring showed that patients who received the vaccine had significantly lower systolic and diastolic blood pressure, compared with those who received placebo (Lancet 2008;371:821-7).
Another emerging treatment is renal denervation, a catheter-based treatment in which radiofrequency is applied to sympathetic nerves in the kidney to help control blood pressure. A randomized trial found that renal denervation reduced blood pressure in treatment-resistant hypertensive patients, compared with those who did not receive the intervention (Lancet 2010;376:1903-9).
Finally, a new potential class of antihypertensive agents, known as vasopeptidase inhibitors, is being studied. These agents inhibit angiotensin-converting enzyme as well as neutral endopeptidase, an enzyme that helps rid the body of excess salt and water and would lower the blood pressure, she said.
Dr. Harper said that she had no relevant financial disclosures to make.