Hypertension is turning out to be more prevalent and more diverse than previously thought. Also, slight elevations of blood pressure are apparently more dangerous than the diagnosis of "mild hypertension" would imply.
Even as new studies point up the health benefits of sustained treatment with anti-hypertensive agents, compliance rates remain alarmingly low. Despite an army of 68 anti-hypertensives on the market, in only 21% of the estimated 50 million-plus Americans with hypertension is the condition properly controlled.
Not that pharmacists aren't trying.
"We advise patients just how important it is that they continue their blood pressure therapy," says Scott Hendren, pharmacist at Consumer's IGA in Stillwater, Okla. "We find that people are generally good about complying. They seem to only skip a dose now and then, as opposed to going off the medication completely."
"While we do oral counseling, we supplement it with a patient leaflet that the customer can take home and read thoroughly," says Bill Cantagallo, a pharmacist at Food Circus Supermarkets, Wall, N.J. "Plus, we have a nurse who comes in on Wednesdays to take people's blood pressure, and that's pretty popular."
"Patients complain that the medications are very expensive," adds Cantagallo. "But I try to impress upon them that hypertension, if left untreated, can create problems later on in life."
The new findings on hypertension were generated by several major studies all conducted last year. Much of the new thinking about hypertension is contained in the "Fifth Report of the Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure," known as JNC V.
To emphasize that there is nothing "mild" about mild hypertension, the authors of the 1993 JNC V report have renamed it "Stage 1 hypertension."
A broader definition of hypertension adopted in the JNC V report means that more people than ever are designated as having the condition. Stage 1 hypertension encompasses all systolic pressures between 140 mm and 159 mm Hg or diastolic pressures between 90 mm and 99 mm Hg. This follows studies showing that people in these categories are at substantially greater risk for premature death as well as a long list of cardiovascular and renal complications.
The report also stresses that diuretics and beta-blockers are the only anti-hypertensive drug classes that have been proved to reduce cardiovascular-related death. The two classes are strongly encouraged as first-line therapy unless contraindicated or poorly tolerated.
Despite this recommendation, it's becoming clear that there is no one "magic bullet" for treating hypertension that works for everyone. Some people respond better to certain treatments than to others. The variety of anti-hypertensive prescriptions dispensed bears this out.
Pharmacies pretty much run the gamut when it comes to high blood pressure medications dispensed. "Our big sellers are probably Dyazide and the ACE [angiotensin-converting-enzyme] inhibitors, mostly Vasotec and Calan," says Cantagallo at Food Circus.
"We see mostly Cardizem CD," says Hendren. "Procardia is still hanging in there along with Vasotec, and we have a few patients on HCTZ [hydrochlorothiazide]," he adds.
It is worth noting that in its new definition of hypertension, JNC V includes systolic as well as diastolic abnormalities. It used to be the bottom number was the important one to watch. No more.
A study that was part of the Framingham Heart trials and published in the New England Journal of Medicine Dec. 23, 1993, found that initially mild systolic hypertension progressed to the more severe type in 80% of subjects monitored. The study, which followed more than 2,000 adults for three decades, found that those over age 60 with untreated Stage 1 or mild hypertension were at increased risk of developing cardiovascular disease because of their hypertension, and that Stage 1 hypertension was the most common untreated type among this age group.
"The implications of this study are especially important in the elderly, in whom systolic hypertension is so prevalent," says Dr. Aram V. Chobanian, dean of the Boston University School of Medicine.
In light of these findings, earlier interventions to prevent the progression of systolic hypertension to more severe hypertension would seem justified, just as they are to control diastolic hypertension. But what is the right way to intervene initially? Anti-hypertensive drugs? Low-salt, low-fat diets? Two hours daily on the Stairmaster?
A pair of recently published studies found two different approaches to be effective in treating Stage 1 hypertension. One approach relied only on drugs; the other involved behavior modification plus drugs.
The "Veterans Administration Cooperative Study Group on Anti-Hypertensive Agents," published in the New England Journal of Medicine April 1, 1993 compared representatives of six classes of high blood pressure medications. Alpha-adrenergic blockers, beta-adrenergic blockers, thiazides, alpha-agonists, calcium channel blockers and ACE inhibitors were tried as monotherapy in 1,292 men, half of whom were black. Among the findings:
Single-drug therapy lowered blood pressure to an acceptable level, although there were significant differences in how patients responded to individual anti-hypertensive agents.
The most consistent reduction in diastolic pressure was achieved with diltiazem.
In white patients, atenolol and captopril lowered blood pressure for the most people, and for the longest amount of time.
HCTZ and clonidine were the most effective in lowering elevated systolic pressure.
Captopril was the least effective of therapies tested in black patients, a group in whom ACE inhibitors and beta-blockers have been proved less effective. Diltiazem showed particularly good results in black men of all ages.
In white men under age 60, captopril ranked first in reaching blood pressure goals; in white men 60 years and older, the most effective agents were atenolol, diltiazem and captopril.
Prasozin was the least effective of the six drugs tested in lowering blood pressure. Prasozin and clonidine were the least well tolerated of the six.
Bottom line of the Veterans study: Drugs can work alone -- without diet changes -- to reduce high blood pressure. But in males at least, race and age can have an important effect on the success of single-agent anti-hypertensive therapy.
Compare this to results of a four-year study, published in the Journal of the American Medical Association last Aug. 3, that concluded anti-hypertensive drug therapy works best when used in combination with lifestyle interventions.
The "Treatment of Mild Hypertension Study" trial followed 900 males and females, of whom 20% were black, for one year. The study found no significant difference in the efficacy of the five anti-hypertensive drugs from different therapeutic classes when the drugs were accompanied by lifestyle modification for one year. Lifestyle changes were those green-lighted by JNC V: weight reduction, sodium restriction, aerobic exercise and reduction of alcohol intake.
The study concluded that in well-motivated patients with mild to moderate hypertension, lifestyle modification alone is effective in lowering blood pressure and maintaining quality of life, and that such behavioral changes may be more important than which drug the doctor prescribes.
However, if a drug is added to the lifestyle modification, an even better result can be expected, although, unlike the Veterans study, no single drug was found to be significantly better than another. All classes of drugs -- with the exception of the ACE inhibitors -- were equally effective in lowering blood pressure in the study published in JAMA.
Another 1993 study, published in the Archives of Internal Medicine, found that half of 587 overweight, hypertensive patients who lost weight reduced their blood pressure. Patients only had to lose an average of 7 pounds to bring their pressure down to normal. Another factor to consider in controlling blood pressure and encouraging patients to comply with their medication regimens is "quality of life."
A study, "Quality of Life and Anti-Hypertensive Therapy in Men: A Comparison of Captopril with Enalapril," published in the New England Journal of Medicine last April 1, favored captopril over enalapril. Both drugs previously had been rated as equal in efficacy and safety.
Researchers are clumsily flirting with the explanation that ACE inhibitors may have some anti-anxiety properties as well as improve cognitive function. The difference between these two ACE inhibitors, the researchers speculate, may have to do with how the physiochemical characteristics of each drug affect their distribution into the central nervous system. Regardless of which studies are right, or whether all studies are right, the message to the public is vexing. Human nature says when in doubt, do nothing.
But like an unruly child, hypertension rarely corrects itself. Instead, it renders the organs useless. End organ effects of uncontrolled hypertension include hemorrhages that cause brain tissue destruction, left ventricular hypertrophy, renal failure and retinal lesions leading to blindness.
Pharmacists need to impress upon patients that anti-hypertensive therapy, whether through medication or lifestyle changes, or both, is needed to prevent such serious problems, sort of like a savings account for one's health.
The next time a patient on an anti-hypertensive medication comes in for a refill, the pharmacist should check the profile to make sure the patient is compliant. Pharmacists should try to get patients interested in taking even small steps that will lower their blood pressure.
Pharmacists also should encourage patients to keep track of their condition even if it sometimes means taking patients' blood pressure in the store. Seeing their blood pressure go down as a result of taking medication as directed or making lifestyle changes, or both, may be just the feedback patients need to stay compliant.