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Blood Pressure Measurements at Emergency Department Visits by Adults: United States, 2007-2008
 
 
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Richard W. Niska, M.D., M.P.H., F.A.C.E.P.

reported in a National Center for Health Statistics Data Brief

HHS CDC

the study looked at data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) ED visit files from 2007 to 2008, and for comparison, at the NHAMCS OPD and National Ambulatory Medical Care Survey (NAMCS) physician office files from the same time period. Older patients, men, blacks, Medicare beneficiaries, and the uninsured were disproportionately affected.

Key findings

Data from the National Hospital Ambulatory Medical Care Survey


· Blood pressure (BP) is severely elevated at 16.3%, and moderately elevated at 27.2%, of hospital emergency department (ED) visits. Severely and moderately elevated BPs are more common at ED visits than at visits to patients' primary care providers in hospital outpatient departments and physician offices.

· Severely and moderately elevated BPs are more common at ED visits by older age groups and men.

· Severely elevated BP is more common at ED visits by non-Hispanic black persons (19.7%) than by non-Hispanic white (15.3%) or Hispanic (15.3%) persons.

· Severely elevated BP is more common at ED visits by Medicare beneficiaries (19.6%) than by those with private insurance (16.3%) or Medicaid (14.1%), even when adjusted for age. Moder

Persistently elevated blood pressure (BP), or hypertension, is a major risk factor for atherosclerotic cardiovascular disease, congestive heart failure, and renal failure. In 2007-2008, 29% of U.S. civilians had hypertension. Only one-half of persons with hypertension had their BP under control, with lower rates for persons aged 18-39 years and Hispanic persons (1). Because elevated BP in the emergency department (ED) may reflect underlying hypertension, the American College of Emergency Physicians recommends that patients with systolic BP greater than 140 mm Hg or diastolic BP greater than 90 mm Hg be referred for follow-up (2). This brief describes the distribution of elevated BP readings in the ED. The data are presented by severity level because the risk of complications increases with the severity of underlying hypertension (3).

Summary

This brief shows that elevated BP readings are much more common at visits to the ED than at visits to outpatient primary care providers. Compared with the 27.0% prevalence found at visits to primary care providers, the combined visit prevalence of severely and moderately elevated BP in EDs is about 43.5%. Disproportionately affected subgroups include patients who are older, male, non-Hispanic black, Medicare beneficiaries, or uninsured.

One reason that elevated BP may be observed more frequently in the ED than at visits to primary care providers is that adults in less than optimal general health are more likely to use the ED than those in good health (4). Two national objectives related to prevention of heart disease and stroke are (a) to reduce the proportion of adults with hypertension and (b) to increase the proportion of adults with hypertension whose BP is under control (5). ED visits could provide opportunities to address elevated BP through patient education, initial treatment, and referral to primary care as deemed clinically appropriate.

Elevated BP is more common at ED visits by older patients and men.

· The prevalence of severely elevated BP increases significantly for each older age group up to age 65 (Figure 2). There is no significant difference in the prevalence between age groups 65-74 years and 75 years and over.

· The prevalence of moderately elevated BP increases significantly for each older age group up to age 45 years. There are no significant differences among age groups 45-64 years, 65-74 years, and 75 years and over.

· The prevalences of both moderately elevated (30.8%) and severely elevated (16.9%) BPs are significantly greater at ED visits by men compared with women (Figure 3).

Severely elevated BP is more common at ED visits by non-Hispanic black persons than by non-Hispanic white or Hispanic persons.

· Compared with non-Hispanic black persons (19.7%), the age-adjusted prevalence of severely elevated BP was significantly less at ED visits by non-Hispanic white (15.3%) and Hispanic (15.3%) persons (Figure 4).

· Compared with non-Hispanic white persons, the age-adjusted prevalence of moderately elevated BP was significantly less at ED visits by Asian persons.

Elevated BP is more common at ED visits by Medicare beneficiaries and by uninsured patients.

· ED visits with Medicare as the primary expected payment source had the highest age-adjusted prevalence of severely elevated BP (19.6%) (Figure 5). The prevalence was significantly less at ED visits by patients with private insurance (16.3%) or Medicaid (14.1%).

· ED visits with Medicaid as the primary expected payment source had the lowest age-adjusted prevalence of moderately elevated BP (23.7%). The prevalence was significantly greater at ED visits by patients with private insurance (27.7%) and the uninsured (27.3%).

Definitions

BP levels: The BP abstracted into the ED Patient Record Form is the first BP reading to be recorded in the medical record for that visit. BP measurements were classified hierarchically starting with the more severely elevated measurement, followed by moderately elevated, mildly elevated, and not elevated, based on the criteria of the Seventh Joint National Committee (JNC-7) (3). BP was subdivided into four levels, which are summarized here for completeness. The current analysis concentrated on severely and moderately elevated BPs.

· Severely elevated. Systolic 160 mm Hg or above or diastolic 100 mm Hg or above, corresponding to the JNC-7 stage 2 hypertension category.

· Moderately elevated. Systolic 140-159 mm Hg or diastolic 90-99 mm Hg, corresponding to the JNC-7 stage 1 hypertension category.

· Mildly elevated. Systolic 120-139 mm Hg or diastolic 80-89 mm Hg, corresponding to the JNC-7 prehypertension category.

· Not elevated. Systolic less than 120 mm Hg and diastolic less than 80 mm Hg (recorded as P, PALP, DOPP, or DOPPLER, or left blank) (6).

About 4.2% of ED visits and 8.9% of primary care provider visits had no systolic BP recorded. These visits were deleted from the analysis.

 
 
 
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