The New "Normal" Blood Pressure
Background: In 2003, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure redefined normal blood pressure (BP) as less than 120/80 mm Hg and added the category of prehypertension, recommending that such patients receive counseling on lifestyle modifications. Based on population data, 41.8% of US adults have normal BP, 31% have prehypertension, and the remainder has hypertension. These percentages may not reflect the proportions seen in family medicine practices. The purposes of this study were to describe the proportion of adults in a family medicine practice with normal BP and the proportions with prehypertension and hypertension and to examine associations with having normal BP.
Methods: Records of 633 nonpregnant adults from a large family medicine clinic were reviewed for demographic and BP information. Proportions of subjects in each BP category (normal, prehypertension, or hypertension) were determined. Characteristics associated with normal BP were examined using X tests and logistic regression.
Results: Nearly 80% of adults in this population had prehypertension or hypertension. Subjects more likely to have normal BP were young, female, white, and not overweight/obese. Almost 60% of subjects had documented hypertension, were receiving antihypertensive medications, or had a BP on the day of visit ≥140/90 mm Hg. Over 20% had prehypertension.
Conclusion: The proportion of adult family medicine patients with normal BP is low. Counseling 20% of adult patients about prehypertension while continuing to strive to improve BP control for the 60% of patients with hypertension could pose a new challenge to clinicians working in family medicine offices.
The nature of a clinician's work is to collect information so that a decision can be made regarding a course of action to improve a person's health. Such work often dictates that complex information be viewed in a way that can contribute to a decision that something is either normal or abnormal. In medicine, this notion often means that data based on a continuous scale must be dichotomized. In current practice, such has traditionally been the case with blood pressure (BP). Through a series of repeat BP measurements over time, a clinician makes a decision whether or not to make a diagnosis of hypertension. This decision is generally based on a threshold above that BP -- taking into account various comorbidities -- considered elevated enough to justify treatment with medications to reduce cardiovascular disease (CVD) risk. For most patients, this threshold is sustained office BPs greater than 140 mm Hg systolic or 90 mm Hg diastolic.
In 2003, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) defined a new category of BP called prehypertension. The prehypertension category includes nonhypertensive adults with BP between 120 to 139 mm Hg systolic or 80 to 89 mm Hg diastolic. JNC 7 states that such patients "... require health-promoting lifestyle modifications to prevent CVD." These lifestyle modifications include weight loss (if overweight); increased physical activity; increased intake of whole grains, fruits, and vegetables; and moderation of alcohol intake. Such lifestyle modifications are of course advisable for all individuals regardless of BP status. The assumption is that patients with prehypertension would receive more intensive, or targeted, advice. The previous JNC 6 report, published in 1997, defined the range of BP 130 to 139 mm Hg systolic or 85 to 89 mm Hg diastolic as high-normal. BPs below this range, including those 120 to 129 mm Hg systolic and 80 to 84 mm Hg diastolic, were considered normal. JNC 7 has in effect, expanded the number of individuals considered abnormal.
Normal BP is now defined as systolic BP less than 120 mm Hg and a diastolic BP less than 80 mm Hg. A recent population-based study demonstrated that 41.8% of US adults have normal BP. However, this proportion may not reflect the proportion of patients with normal BP in the family medicine office. The purposes of this study were to estimate (1) the proportion of adults in a family medicine practice who actually have normal BP and describe characteristics of such patients; and (2) the proportions of adult patients in a family medicine practice who have prehypertension and hypertension.
Abstract and Introduction
Abstract
Background: In 2003, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure redefined normal blood pressure (BP) as less than 120/80 mm Hg and added the category of prehypertension, recommending that such patients receive counseling on lifestyle modifications. Based on population data, 41.8% of US adults have normal BP, 31% have prehypertension, and the remainder has hypertension. These percentages may not reflect the proportions seen in family medicine practices. The purposes of this study were to describe the proportion of adults in a family medicine practice with normal BP and the proportions with prehypertension and hypertension and to examine associations with having normal BP.
Methods: Records of 633 nonpregnant adults from a large family medicine clinic were reviewed for demographic and BP information. Proportions of subjects in each BP category (normal, prehypertension, or hypertension) were determined. Characteristics associated with normal BP were examined using X tests and logistic regression.
Results: Nearly 80% of adults in this population had prehypertension or hypertension. Subjects more likely to have normal BP were young, female, white, and not overweight/obese. Almost 60% of subjects had documented hypertension, were receiving antihypertensive medications, or had a BP on the day of visit ≥140/90 mm Hg. Over 20% had prehypertension.
Conclusion: The proportion of adult family medicine patients with normal BP is low. Counseling 20% of adult patients about prehypertension while continuing to strive to improve BP control for the 60% of patients with hypertension could pose a new challenge to clinicians working in family medicine offices.
Introduction
The nature of a clinician's work is to collect information so that a decision can be made regarding a course of action to improve a person's health. Such work often dictates that complex information be viewed in a way that can contribute to a decision that something is either normal or abnormal. In medicine, this notion often means that data based on a continuous scale must be dichotomized. In current practice, such has traditionally been the case with blood pressure (BP). Through a series of repeat BP measurements over time, a clinician makes a decision whether or not to make a diagnosis of hypertension. This decision is generally based on a threshold above that BP -- taking into account various comorbidities -- considered elevated enough to justify treatment with medications to reduce cardiovascular disease (CVD) risk. For most patients, this threshold is sustained office BPs greater than 140 mm Hg systolic or 90 mm Hg diastolic.
In 2003, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) defined a new category of BP called prehypertension. The prehypertension category includes nonhypertensive adults with BP between 120 to 139 mm Hg systolic or 80 to 89 mm Hg diastolic. JNC 7 states that such patients "... require health-promoting lifestyle modifications to prevent CVD." These lifestyle modifications include weight loss (if overweight); increased physical activity; increased intake of whole grains, fruits, and vegetables; and moderation of alcohol intake. Such lifestyle modifications are of course advisable for all individuals regardless of BP status. The assumption is that patients with prehypertension would receive more intensive, or targeted, advice. The previous JNC 6 report, published in 1997, defined the range of BP 130 to 139 mm Hg systolic or 85 to 89 mm Hg diastolic as high-normal. BPs below this range, including those 120 to 129 mm Hg systolic and 80 to 84 mm Hg diastolic, were considered normal. JNC 7 has in effect, expanded the number of individuals considered abnormal.
Normal BP is now defined as systolic BP less than 120 mm Hg and a diastolic BP less than 80 mm Hg. A recent population-based study demonstrated that 41.8% of US adults have normal BP. However, this proportion may not reflect the proportion of patients with normal BP in the family medicine office. The purposes of this study were to estimate (1) the proportion of adults in a family medicine practice who actually have normal BP and describe characteristics of such patients; and (2) the proportions of adult patients in a family medicine practice who have prehypertension and hypertension.
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