One of the most insidious risk factors for heart attacks, heart failure, strokes and kidney failure got a make-over last week. It turns out that this risk factor, hypertension or high blood pressure, is even more of a problem than previously recognized. The panel of experts that periodically reviews the available data on the risks, available treatments and establishes the guidelines for doctors is called the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. In last week's Journal of the American Medical Association, the Joint National Committee issued its seventh iteration of its guidelines, colloquially called JNC 7.
When the U.S. population has been surveyed, it has been determined that even with the awareness of the condition and treatment modalities available, only 25% of the American population have their blood pressure adequately controlled by the old JNC 6 standards. There is a doubling of risk for each 20-point rise in the top number, called the systolic pressure, or 10-point rise in the bottom number, the diastolic pressure. And these risks are more significant if one is over age 50.
With the new JNC 7 guidelines, millions of people who thought they had “normal” blood pressure will be reclassified. These new federal guidelines affect people with blood pressures as low as 120 over 80 up to the previously upper limit of 140/90 millimeters of mercury.
About 45 million Americans are in this prehypertensive range, and appear to be at increased risk of the long term complications of high blood pressure. The change comes from scientific studies showing the risk of heart disease begins at blood pressures lower than previously thought, perhaps as low as 115/75. One should not be overly concerned about modest fluctuations in blood pressures above and below these numbers since biologic systems, like people, have normal variations over time. Also, blood pressure, like all cardiovascular risk factors, is not “all on” or “all off.” By that I mean that blood pressure numbers, blood fat values, blood sugar levels and the others add statistical risk to the development of cardiovascular disorders. They do not mean 100% chance of getting heart disease if you have the risk factor, nor does the absence of a risk factor mean you are home free.
In reviewing the recent medical literature, the JNC 7 report notes that combination therapy will likely be required to get optimal control of high blood pressure. Fortunately, as I reviewed in an earlier column, the most common first or second drug should be the tried and true, generically available, and inexpensive diuretic. Depending on the particulars of the patient's situation, the other first or second drug can be chosen from several classes of drugs that have also shown efficacy. Increasingly, these drugs may also have generic equivalents.
One very welcome recommendation in the JNC 7guidelines is the encouragement for doctors to be far more aggressive in diagnosing and treating high blood pressure. Those same surveys that showed that only a quarter of high blood pressure patients were adequately treated also showed that almost a third of people with high blood pressure were not even aware they had it.
And remember that lifestyle changes still are the first interventions to be recommended if the blood pressure elevation is mild. People with prehypertension should lose weight if they are overweight, get regular physical activity, avoid salty foods and drink no more than two alcoholic beverages a day. If those interventions do not bring the blood pressure into more acceptable ranges, then medications may be required.
As always, the best person to help you with these recommendations and to sort out all your possible risk factors is your doctor. But first, you have to show up.