According to the "5 Minute Clinical Consult" textbook, 20 percent of the American population has hypertension. Normal blood pressure is 120mm Hg or less systolic and 80mm Hg or less diastolic. Hypertension is defined as greater than two or more elevated blood pressures on more than two visits. Traditionally high blood pressure was considered anything greater than 140mm Hg systolic and greater than 90mm Hg diastolic. New data has changed the hypertension guidelines.
Risk of Stroke and Death
The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure presents observational data on more than a million people indicating that the risk of stroke and death increases with blood pressure levels as low as 115mm Hg systolic and 75mm Hg diastolic and upward. For every 20mm Hg increase in blood pressure, mortality rates double from both ischemic heart disease and stroke, according to the Joint National Committee.
Pre-Hypertension
Pre-hypertension is not considered a disease category but a classification to identify individuals at high risk of developing hypertension. According to the Joint National Committee, pre-hypertension is defined as 120mm Hg to 139mm Hg systolic and 80mm Hg to 89mm Hg diastolic. These patients are not candidates for drug therapy but need to be encouraged strongly to make lifestyle changes to prevent progression to hypertension. Lifestyle changes include a low-salt, low-fat diet, regular exercise, smoking cessation and good sleeping habits. Patients identified as pre-hypertensive who already have diabetes or kidney disease should be started on drug therapy after a trial of lifestyle modifications have failed. The goal is to lower the blood pressure to normal levels with lifestyle changes and prevent the progressive increase in blood pressure.
Importance of Systolic Blood Pressure
According to the Joint National Committee, significant data warrant greater attention to systolic blood pressure. An increase in systolic blood pressure is a risk factor for cardiovascular disease. The blood pressure changes with age and the rise in systolic pressure continues through a lifetime, whereas the increase in diastolic pressure seems to level off around age 50. Systolic hypertension is the predominant form of hypertension in people aged 50 and older. Controlling systolic hypertension reduces mortality from cardiovascular, stroke and heart failure events. The Joint National Committee states that without better systolic blood pressure control, as the population ages, there will be an increase in overall rates of cardiovascular disease and kidney failure.
References
- "5 Minute Clinical Consult 2010"; Frank J. Domino, Editor; 2009
- The National Institutes of Health: The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure
