Richard W. Niska, MD, MPH, FACEP
CAPT, US Public Health Service
Introduction
 Emergency physicians refer to primary care specialists for follow-
up of conditions identified in the emergency department (ED).
 The American College of Emergency Physicians (ACEP)
recommends that patients with high blood pressure (BP) be
referred for possible hypertension.


Decker et al. Clinical policy: critical issues in the evaluation and management of adult patients with
asymptomatic hypertension in the ED. Ann Emerg Med. 2006; 47(3):237-49.
Tilman et al. Recognizing asymptomatic elevated BP in ED patients: how good (bad) are we? Am J
Emerg Med. 2007; 25(3):313-7.
 7% of ED patients with asymptomatic high BP were diagnosed, treated, or
referred for their BP.
 No differences were found by age, sex, race or insurance status between
patients receiving attention for high BP and not receiving it.
Hypothesis and objective
 Hypothesis:
 High BP readings would trigger a diagnosis of possible
hypertension, to facilitate outpatient referral to:


establish a formal diagnosis and begin treatment
alter management of poorly controlled hypertensive patients
 Objective:
 To examine factors associated with diagnosing possible
hypertension in ED patients with high BP
Methods
Inclusion criteria
 Data from the 2003-2008 National Hospital
Ambulatory Medical Care Survey ED visit files
 All visits by patients 18 years of age or older
 BP > 139 mm Hg systolic or > 89 mm Hg diastolic

BP missing for 4.5% - not statistically different among years
Exclusion criteria:
Diagnoses excluded in ACEP clinical policy
 Acute hypertensive emergencies
 Acute myocardial infarction
 Intracranial hemorrhage
 Hypertensive encephalopathy
 Cerebral aneurysm
 Ischemic stroke
 Aortic aneurysm
 Acute renal failure
Exclusion criteria:
Dispositions precluding outpatient referral
 Admission to hospital, intensive care, coronary care or





observation units
Transfer to different hospital
Death in the ED
Dead on arrival
Leaving without being seen (before or after medical
screening exam)
Leaving against medical advice
Dependent variable
 Whether or not hypertension was recorded as a diagnosis at the ED visit
 ICD-9 codes:
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401: essential hypertension
402: hypertensive heart disease
403: hypertensive chronic kidney disease
404: hypertensive heart and chronic kidney disease
405: secondary hypertension
 Diagnoses could be coded as:




Probable
Questionable
Rule-out
Definitive diagnoses not so coded
 Three diagnoses possible on data abstraction instrument
Independent variables:
JNC-7 stage of BP elevation
 Systolic BP criteria
 Systolic BP 140-159
 Systolic BP 160 or greater
(stage 1 systolic BP elevation)
(stage 2 systolic BP elevation)
 Diastolic BP criteria
 Diastolic BP 90-99
 Diastolic BP 100 or greater
(stage 1 diastolic BP elevation)
(stage 2 diastolic BP elevation)
 Final variable defined hierarchically (either systolic or diastolic BP at
higher level)
 Either systolic or diastole BP at stage 2
 Then either systolic or diastolic BP at stage 1
(stage 2 BP elevation)
(stage 1 BP elevation)
Chobanian et al. Seventh report of the Joint National Committee (JNC-7) on Prevention,
Detection, Evaluation, and Treatment of High BP. Hypertension. 2003; 42:1206-52.
Independent variables:
Age
 High home BP in patients with 2 hypertensive ED readings was associated with
older age.
 Tanabe et al. Increased BP in the ED: pain, anxiety, or undiagnosed
hypertension? Ann Emerg Med. 2008; 51(3):221-9.
 Age groups:
 18-30 years
 31-45 years
 46-60 years
 60 years or older
 Cutoffs chosen to include about ¼ of sample in each age group (close to
median and 25th/75th percentiles)
 Avoid potential collinearity with Medicare eligibility in multivariate analysis by
not using age 65 as a cutoff
Independent variables:
Sex
 Male
 Female
Independent variables:
Race-ethnicity
 Non-Hispanic white
 Non-Hispanic black
 Hispanic (white or black)
 Other (collapsed due to small sample sizes)
 Asian
 Native Hawaiian or other Pacific Islander
 American Indian or Alaska Native
 Multiracial
Independent variables:
Primary payment source

Ability to make phone appointments with primary care providers in Washington, DC, differed by payment source:
71 % of hypothetical privately insured patients
37% of hypothetical Medicaid patients
13% of hypothetical uninsured patients
Blanchard et al. Access to appointments based on insurance status in Washington, D.C. J Health Care Poor Underserved. 2008;
19(3):687-96.
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
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Ability to make phone appointments with clinics for urgent ED follow-up in 9 US cities differed by payment source:
Two thirds of research assistants claiming private insurance
No difference between privately insured and those offering cash payment in full
34% of research assistants claiming Medicaid
25% of research assistants claiming being uninsured
Asplin BR, Rhodes KV, Levy H, et al. Insurance status and access to urgent ambulatory care follow-up appointments. JAMA.
2005; 294(10):1248-54.
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Primary payment source categories:
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Private insurance
Medicare
Medicaid
Worker’s compensation
No insurance (self-pay, no charge, charity)
Other
Unknown
Independent variables:
Survey year
 2003-2006
 Baseline period before publication of ACEP policy
 2007
 2008
Independent variables:
Pain severity
 Tanabe et al. also found that:
 High ED BP was slightly correlated with increased pain scores
 Most patients without a history of hypertension who had high
BP in ED also had high home BPs.
 Pain severity categories:
 No pain
 Mild
 Moderate
 Severe
 Unknown
Independent variables:
Metropolitan statistical area
 Metropolitan (urban)
 Non-metropolitan (rural)
Statistical Methods
Bivariate analysis
 Associations between dependent variable and all
independent variables
 Chi-squares in SUDAAN 9.1
 PROC CROSSTAB
 Alpha < 0.05
Multivariate analysis
 Logistic regression model to determine significant
predictors of diagnosing possible hypertension
 All independent variables included in initial model
 Stepwise backward elimination according to highest
Wald p-value till all p-values less than 0.05
 Odds ratios (OR) with 95% confidence intervals (CI)
Results
Analysis of adults with high BP
 Number of adult ED visits in 2003-2008 at which BP
was high:
 50,444 unweighted visits
 Represents weighted national estimate of about 167
million visits
 5.5% diagnosed with possible hypertension
 Similar to Tillman (2007): 7% diagnosed, treated or referred
Bivariate analysis
 Significant associations (all p<0.01)
 BP elevation stage
 Age
 Sex
 Race-ethnicity
 Pain severity
 Payment source
 Payment source:
 Dropped out of multivariate model after adjustment for all other covariates
 Replicates Tillman (2007): no differences by insurance status in addressing high BP
Hypertension diagnosis more likely:
Increasing stage of high BP
14.0
 Stage 2
12.0
 OR 4.96 (95% CI 4.31–5.71)
10.0
P<0.01
 Stage 1
 Reference group
Percent

8.0
6.0
11.3
4.0
2.0
2.2
0.0
Stage 1
Stage 2
Stage of BP elevation
Percent of emergency department visits by adult patients with high blood
pressure (BP) who were given a diagnosis of possible hypertension, by
stage of BP elevation: United States, 2003-2008
Hypertension diagnosis more likely:
Increasing age
 18-30 years
 Reference group
 P<0.01
 46-60 years
 OR 2.52 (95% CI 2.00–3.16)
 P<0.01
Percent of emergency department visits
 31-45 years
 OR 1.77 (95% CI 1.40–2.23)
10.0
9.0
8.0
7.9
7.0
7.0
6.0
5.0
4.5
4.0
3.0
2.0
2.1
1.0
 Over 60 years
 OR 2.53 (95% CI 1.98–3.25)
 P<0.01
0.0
18-30 years
31-45 years
46-60 years
61 years and
over
Age
Percent of emergency department visits by adult patients with high
blood pressure who were given a diagnosis of possible
hypertension, by age: United States, 2003-2008
Hypertension diagnosis more likely:
Female sex
8.0
 Female
7.0
 OR 1.17 (95% CI 1.06–1.28)
6.0
P<0.01
 Male
 Reference group
Percent

5.0
4.0
3.0
6.2
4.7
2.0
1.0
0.0
Female
Male
Sex
Percent of emergency department visits by adult patients
with high blood pressure who were given a diagnosis of
possible hypertension, by sex: United States, 2003-2008
Hypertension diagnosis more likely:
Minority ethnic groups

P<0.01
 Hispanic (white or black)
 OR 1.52 (95% CI 1.25–1.83)

P<0.01
 Other
 OR 1.61 (95% CI 1.24–2.09)

P<0.01
12.0
Percent of emergency department visits
 Non-Hispanic white
 Reference group
 Non-Hispanic black
 OR 2.39(95% CI 2.05–2.78)
10.0
8.0
6.0
9.2
4.0
6.8
5.7
2.0
4.1
0.0
Non-Hispanic Non-Hispanic
Hispanic
white
black
Race-ethnicity
Other
Percent of emergency department visits by adult patients with high blood
pressure who given a diagnosis of possible hypertension, by raceethnicity: United States, 2003-2008
Hypertension diagnosis more likely:
Decreasing pain level
 No pain
 OR 2.18 (95% CI 1.86–2.55)

P<0.01
 Mild pain
10.0
 OR 1.27 (95% CI 1.06–1.52)
P=0.01
 Moderate pain
 OR 1.13 (95% CI 0.96–1.32)

 Reference group
 Unknown
 OR 1.45 (95% CI 1.21–1.75)


6.0
4.0
Not significant
 Severe pain

8.0
Percent

95% confidence Interval
12.0
P<0.01
Does this category really mean “no pain?”
Less likely to record pain when not an issue?
2.0
0.0
No pain
Mild
Moderate
Severe
Unknown
Pain severity
Percent of emergency department visits by adult patients with
high blood pressure who were given a diagnosis of possible
hypertension, by pain severity: United States, 2003-2008
Limitations
 Evaluating the effect of a clinical policy on referral would
be more precisely done by studying referral directly.
 But survey referral variables not tied to a specific diagnosis.
 Results should be interpreted with caution since we do not
know whether diagnosing hypertension would actually
lead to referral.
 Survey allows abstraction of up to 3 diagnoses
 Possible that hypertension diagnosis not abstracted if there
were 3 or more higher-priority diagnoses
 However, we found blank entries in:
 84.8% of 3rd diagnosis fields
 56.8% of 2nd diagnosis fields
 0.6% of 1st diagnosis fields
 These blank fields were available to abstract a hypertension
diagnosis if one existed in the medical record.
Conclusions
Survey year
 No improvement in diagnosing possible hypertension in 2007 or 2008
compared to the years before, during, and immediately after the
clinical policy on referral was published.

Lehrmann et al. Knowledge translation of the ACEP clinical policy on hypertension. Acad Emerg Med.
2007; 14(11):1090-6.
 Studied referral rates of patients with high BP by emergency
physicians at 2 centers before and after dissemination of the ACEP
clinical guideline


13% referred before policy dissemination
7% afterwards
 More research needed for later years, since this policy is on the 2009 Lifelong Learning &
Self Assessment reading list of the American Board of Emergency Medicine
 Passing tests on readings are required to maintain emergency medicine certification
 Improvement expected as more ED physicians become sensitized to the need for referral
Stage of BP elevation
 Five-fold increased likelihood of possible hypertension
diagnosis when BP is stage 2 compared to stage 1
 Baumann et al. Provider self-report and practice: reassessment and referral of
ED patients with elevated BP. Am J Hypertens. 2009; 22(6):604-10.
 Mean threshold at which providers would refer patients
was 150/93
 Mean BP of adult ED patients who actually received a
referral for outpatient management was 170/97.
Age
 All groups older than 30 years more likely to be diagnosed with hypertension than those
18-30 years old
 Different from Tillman (2007): no difference by age in addressing high BP.
 But younger patients might stand to benefit from early management of their
hypertension, even though it is less prevalent in that age group.

Ostchega et al. Hypertension awareness, treatment, and control – continued disparities in adults: US, 20052006. NCHS data brief no. 3. Hyattsville, MD: National Center for Health Statistics. 2008.
 Significant differences in the prevalence of hypertension among adults:

age 18-39 years (7%)

age 40-59 (about 1/3)

age 60 and older (67 %)
 5% age 18-59 years and 12% age 60 and older had hypertension and had never been told by
a health care provider that they had it.
 Not referring ED patients of any age with a high BP reading may represent a significant
missed opportunity in controlling hypertension.
Race-ethnicity
 In contrast to a priori expectation that disparities would be
demonstrated for minority patients, our findings strongly predicted:
 increased likelihood of diagnosis for non-Hispanic black & Hispanic
(p<0.01)
 less strongly predictive but still significant (p=0.02) for other ethnicities
 Different from Tillman (2007): no differences by race in addressing high BP
 Ostchega et al. found that U.S. prevalence of hypertension was:
 highest among non-Hispanic black persons (41 percent)
 lower in Mexican-American persons (22 percent)
 Both groups significantly different from non-Hispanic white (28%)
 More research is needed on the impact of race-ethnicity on diagnostic
sensitivity, especially if disparities do not apply universally to all
minority groups
Pain
 Controversial tendency to view high BP as a manifestation of pain, rather than indicative
of possible hypertension
 The finding that possible hypertension is more often diagnosed when pain is absent or
mild is consistent with this belief.

Svenson & Repplinger. Hypertension in the ED: still an unrecognized problem. Am J Emerg Med. 2008; 26(8):913-7.
 No correlation between high BP and pain scores in either adults or children
 Follow-up for high BP only recommended for 4% of patients in their ED

Fleming et al. Detection of hypertension in the ED. Emerg Med J. 2005; 22(9):636-40.
 No correlation between pain scores and mean BP in their ED
 62% of subjects with pain scores >5 of 10 still had high BPs on follow-up when pain scores
no longer elevated
 More research is needed to determine whether high BP readings are a manifestation of
underlying hypertension, regardless of pain severity.
Sex
 Being female was a predictor of receiving a diagnosis of
possible hypertension:
 Association not as strong as other factors in the model
 Different from Tilman (2007): no differences by sex in addressing
high BP
 More research needed to replicate findings
What does it mean?
 Increased referral of patients with high BPs could have
significant public health benefits in the prevention of
cardiovascular complications from chronic hypertension.
 Increased vigilance to diagnose and refer patients with high
BP readings is indicated for:
 Younger patients
 Men
 Patients in moderate to severe pain