Emergency department hypertension and regression to the mean

Electronic health record-derived outcomes in obstructive sleep apnea managed with positive airway pressure tracking systems

STUDY OBJECTIVES

To assess the effectiveness of continuous positive airway pressure (CPAP) management guided by CPAP machine downloads in newly diagnosed patients with obstructive sleep apnea (OSA) using electronic health record-derived health care utilization, biometric variables, and laboratory data.

METHODS

Electronic health record data of patients seen at the University of Utah Sleep Program from 2012-2015 were reviewed to identify patients with new diagnosis of OSA in whom CPAP adherence and residual apnea-hypopnea index as measured by a positive airway pressure adherence tracking device data for ≥ 1 year were available. Biometric data, laboratory data, and system-wide charges were compared in the 1 year before and after CPAP therapy. Subgroups were divided by whether patients met tracking criteria, mean nightly usage, and OSA severity.

RESULTS

976 consecutive, newly diagnosed participants with OSA (median age 55 years, 56.6% male) met inclusion criteria. There was a mean decrease of systolic blood pressure (BP) of 1.2 mm Hg and diastolic BP of 1.0 mm Hg within a year of initiation of CPAP therapy. BP improvements in the subgroup meeting CPAP tracking targets were 1.36 mmHg (systolic) and 1.37 mmHg (diastolic). No significant change was noted in body mass index, glycated hemoglobin, or serum creatinine values within a year of starting CPAP therapy, and health care utilization increased (mean acute care visits 0.22 per year to 0.53 per year; mean charges of $3,997 per year to $8,986 per year).

CONCLUSIONS

An improvement in BP was noted within a year of CPAP therapy in newly diagnosed patients with OSA, with no difference in the magnitude of improvement between those meeting tracking system adherence targets.

CITATION

Locke BW, Neill SE, Howe HE, Crotty MC, Kim J, Sundar KM. Electronic health record-derived outcomes in obstructive sleep apnea managed with positive airway pressure tracking systems. J Clin Sleep Med. 2022;18(3):885-894.

Elevated Blood Pressures Are Common in the Emergency Department but Are They Important? A Retrospective Cohort Study of 30,278 Adults

STUDY OBJECTIVE

We determine the frequency of elevated blood pressure (BP) readings in the emergency department (ED), the proportion of patients with prior or subsequent diagnosis of hypertension assigned in other settings, and the association between ED BP levels and cardiovascular outcomes after ED discharge.

METHODS

This was a retrospective cohort study using electronic medical records for all adults treated and released from a large-volume ED in 2016 that were linked to administrative records for all health care encounters in the province for 2 years before and after the index ED visit. The primary outcome measure was a composite of stroke or transient ischemic attack, acute coronary syndrome, new heart failure, or death.

RESULTS

Of 30,278 adults treated and released from the ED, 14,717 (48.6%) had elevated BP readings; 10,732 (72.9%) had no prior diagnosis of hypertension. Of the 3,480 patients with no prior diagnosis of hypertension but an ED BP greater than or equal to 160/100 mm Hg, 907 (26.1%) subsequently received a diagnosis of chronic hypertension or were prescribed antihypertensive therapy in other settings within 2 years. Among patients without a history of hypertension, those with an ED BP greater than or equal to 160/100 mm Hg were more likely to meet the composite outcome (stroke, transient ischemic attack, acute coronary syndrome, heart failure, or death) in the subsequent year (3.3% versus 2.5%) or 2 years (5.9% versus 3.8%) than those with ED BPs 120 to 139/80 to 89 mm Hg; however, after adjusting for age, sex, diabetes, atrial fibrillation, and prior cardiovascular disease, their risk was not elevated (adjusted hazard ratio 0.84; 95% confidence interval 0.71 to 1.004 during 2 years).

CONCLUSION

Elevated BP readings in the ED are common and are often the first time hypertension is detected; however, they were not associated with adverse cardiovascular outcomes within 2 years of the visit.

National trends in the emergency department management of adult patients with elevated blood pressure from 2005 to 2015

Emergency department (ED)-based screening and referral of patients with elevated blood pressure (BP) are recommended by 2006 and 2013 American College of Emergency Physicians guidelines; however, it is unknown if these recommendations or disparities in care impact clinical practice. The objectives of the study were to assess temporal trends in antihypertensive prescriptions, outpatient follow-up referrals, and diagnosis of hypertension (HTN)/elevated BP and to identify potential disparities by patient characteristics. Using the 2005-2015 National Hospital Ambulatory Medical Care Survey, we examined the frequency and trends over time of antihypertensive prescriptions, outpatient follow-up referrals, and BP diagnoses for US ED visits by adult patients with an elevated triage BP and identified potential disparities in management by patient demography and socioeconomic status. Of the 594 million eligible ED visits by patients from 2005 to 2015, 1.2% (1.0%-1.4%) received antihypertensive prescriptions at discharge, 82.3% (80.0%-83.6%) outpatient follow-up referrals, and 2.1% (1.9%-2.4%) an HTN/elevated BP diagnosis. There were small annual increases over time in the odds of antihypertensive prescriptions at discharge (adjusted odds ratio [aOR] 1.05 [1.00-1.10]), follow-up referrals (aOR 1.04 [1.01-1.07]), and HTN/elevated BP diagnosis (aOR 1.05 [1.02-1.08]). For BPs ≥160/100 mm Hg, prescriptions were more common for Blacks (aOR 2.36 [1.93, 2.88]) and uninsured patients (aOR 1.81 [1.38, 2.38]), and diagnoses were more common for Blacks (aOR 1.95 [1.70, 2.24]) and uninsured patients (aOR 1.30 [1.09, 1.55]). These data suggest little change in and the need for improvement in the management of ED patients with elevated BP, despite the American College of Emergency Physicians guidelines, and raise concern about patient care disparities.

Illustrating Informed Presence Bias in Electronic Health Records Data: How Patient Interactions with a Health System Can Impact Inference

Electronic health record (EHR) data are becoming a primary resource for clinical research. Compared to traditional research data, such as those from clinical trials and epidemiologic cohorts, EHR data have a number of appealing characteristics. However, because they do not have mechanisms set in place to ensure that the appropriate data are collected, they also pose a number of analytic challenges. In this paper, we illustrate that how a patient interacts with a health system influences which data are recorded in the EHR. These interactions are typically informative, potentially resulting in bias. We term the overall set of induced biases informed presence. To illustrate this, we use examples from EHR based analyses. Specifically, we show that: 1) Where a patient receives services within a health facility can induce selection bias; 2) Which health system a patient chooses for an encounter can result in information bias; and 3) Referral encounters can create an admixture bias. While often times addressing these biases can be straightforward, it is important to understand how they are induced in any EHR based analysis.

Blood pressure treatment and outcomes in hypertensive patients without acute target organ damage: a retrospective cohort

OBJECTIVES

The objective is of the study to evaluate the effect of antihypertensive therapy in emergency department (ED) patients with markedly elevated blood pressure (BP) but no signs/symptoms of acute target organ damage (TOD).

METHODS

This is a retrospective cohort study of ED patients age 18 years and older with an initial BP greater than or equal to 180/100 mm Hg and no acute TOD, who were discharged with a primary diagnosis of hypertension. Patients were divided based on receipt of antihypertensive therapy and outcomes (ED revisits and mortality) and were compared.

RESULTS

Of 1016 patients, 435 (42.8%) received antihypertensive therapy, primarily (88.5%) oral clonidine. Average age was 49.2 years, and 94.5% were African American. Treated patients more often had a history of hypertension (93.1% vs 84.3%; difference = -8.8; 95% confidence interval [CI], -12.5 to -4.9) and had higher mean initial systolic (202 vs 185 mm Hg; difference = 16.9; 95% CI, -19.7 to -14.1) and diastolic (115 vs 106 mm Hg; difference = -8.6; 95% CI, -10.3 to -6.9) BP. Emergency department revisits at 24 hours (4.4% vs 2.4%; difference = -2.0; 95% CI, -4.5 to 0.3) and 30 days (18.9% vs 15.2%; difference = -3.7; 95% CI, -8.5 to 0.9) and mortality at 30 days (0.2% vs 0.2%; difference = 0; 95% CI, -1.1 to 0.8) and 1 year (2.1% vs 1.6%; difference = -0.5; 95% CI, -2.5 to 1.2) were similar.

CONCLUSIONS

Revisits and mortality were similar for ED patients with markedly elevated BP but no acute TOD, whether they were treated with antihypertensive therapy, suggesting relative safety with either approach.

Emergency department patients with acute severe hypertension: a comparison of those admitted versus discharged in studying the treatment of acute hypertension registry

OBJECTIVES

To compare the characteristics, treatments, and outcomes for emergency department (ED) patients with severe hypertension by disposition (admitted versus discharged home).

METHODS

Studying the Treatment of Acute hyperTension (STAT) is a multicenter registry of 1566 patients with blood pressure ≥180/110 mm Hg who were treated with intravenous antihypertensive medications in an ED or intensive care unit. Presenting and in-hospital variables, and postdischarge outcomes for the 1053 patients in the ED subset were compared by disposition.

RESULTS

In the multivariable analysis, ED patients were less likely to be discharged if >75 years of age (odds ratio [OR] = 0.3, 95% confidence interval [CI] = 0.1-0.9) or if they had shortness of breath (OR = 0.4, 95% CI = 0.2-0.8) or alteration of mental status (OR = 0.1, 95% CI = 0.02-0.9) on arrival. Nondialysis patients with an admission creatinine concentration >1.5 mg/dL were 80% less likely to be discharged than those ≤1.5 mg/dL (OR = 0.2, 95% CI = 0.08-0.5). In the bivariate analysis, patients with a decrease in systolic blood pressure of <10% 2 hours after medication administration were more likely to be admitted than those discharged (57% vs. 44%; P = 0.041). Disposition did not correlate with 90-day or 6-month mortality or 30-day readmission. However, admitted patients had a higher 90-day readmission rate (38% vs. 24%; P = 0.038).

CONCLUSIONS

ED patients with severe hypertension were more likely to be admitted to the hospital if they were >75 years of age, presented with shortness of breath or altered mental status, or had a creatinine >1.5 mg/dL and were not on hemodialysis.

Size of blood pressure reduction from renal denervation: insights from meta-analysis of antihypertensive drug trials of 4,121 patients with focus on trial design: the CONVERGE report

OBJECTIVE

30 mm Hg drops in office systolic blood pressure are reported in trials of renal denervation, but ambulatory reductions are much smaller. This disparity is assumed to have a physiological basis and also be present with antihypertensive drugs.

DESIGN

We examine this office-ambulatory discrepancy through meta-analysis of drug and denervation trials, categorising by trial design.

PATIENTS (STUDIES)

31 drug trials enrolling 4121 patients and 23 renal denervation trials enrolling 720 patients met the criteria.

RESULTS

In drug trials without randomisation or blinding, pressure reductions are 5.6 mm Hg (95% CI 2.98 to 8.22 mm Hg) larger on office measurements than ambulatory blood pressure monitoring (p<0.0001). By contrast, with randomisation and blinding, office reductions are identical to ambulatory reductions (difference -0.88 mm Hg, 95% CI -3.18 to 1.43, p=0.45). For renal denervation, there are no randomised blinded trial results. In unblinded trials, office pressure drops were 27.6 mm Hg versus pretreatment, and 26.6 mm Hg versus unintervened controls. By contrast, ambulatory pressure drops averaged 15.7 mm Hg across all trials. Among those where the baseline ambulatory pressure was not the deciding factor for enrolment (avoiding regression to the mean), ambulatory drops averaged only 11.9 mm Hg.

CONCLUSIONS

Discrepancies in drug trials between office and ambulatory blood pressure reductions disappear once double-blinded placebo control is implemented. Renal denervation trials may also undergo similar evolution. We predict that as denervation trial designs gradually improve in bias-resistance, office and ambulatory pressure drops will converge. We predict that it is the office drops that will move to match the ambulatory drops, that is, not 30, but nearer 13.

High-Risk Patients with Hypertension: Clinical Management Options

Hypertension, one of the most common human diseases worldwide, affects nearly 1 billion individuals. Complaints related to hypertension are commonly evaluated and treated in the acute care settings such as emergency departments and acute care medical clinics. The evaluation, treatment, and disposition of these patients require thorough knowledge of potential complications and treatment options. This manuscript details a structured approach to evaluating high-risk patients with acute hypertension-related complaints and provides recommendations for treatment and disposition.

Assessing regression to the mean effects in health care initiatives

Background

Interventions targeting individuals classified as “high-risk” have become common-place in health care. High-risk may represent outlier values on utilization, cost, or clinical measures. Typically, such individuals are invited to participate in an intervention intended to reduce their level of risk, and after a period of time, a follow-up measurement is taken. However, individuals initially identified by their outlier values will likely have lower values on re-measurement in the absence of an intervention. This statistical phenomenon is known as “regression to the mean” (RTM) and often leads to an inaccurate conclusion that the intervention caused the effect. Concerns about RTM are rarely raised in connection with most health care interventions, and it is uncommon to find evaluators who estimate its effect. This may be due to lack of awareness, cognitive biases that may cause people to systematically misinterpret RTM effects by creating (erroneous) explanations to account for it, or by design.

Methods

In this paper, the author fully describes the RTM phenomenon, and tests the accuracy of the traditional approach in calculating RTM assuming normality, using normally distributed data from a Monte Carlo simulation and skewed data from a control group in a pre-post evaluation of a health intervention. Confidence intervals are generated around the traditional RTM calculation to provide more insight into the potential magnitude of the bias introduced by RTM. Finally, suggestions are offered for designing interventions and evaluations to mitigate the effects of RTM.

Results

On multivariate normal data, the calculated RTM estimates are identical to true estimates. As expected, when using skewed data the calculated method underestimated the true RTM effect. Confidence intervals provide helpful guidance on the magnitude of the RTM effect.

Conclusion

Decision-makers should always consider RTM to be a viable explanation of the observed change in an outcome in a pre-post study, and evaluators of health care initiatives should always take the appropriate steps to estimate the magnitude of the effect and control for it when possible. Regardless of the cause, failure to address RTM may result in wasteful pursuit of ineffective interventions, both at the organizational level and at the policy level.

Determinants of achieving early blood pressure control with monotherapy in a primary care setting

This study sought to identify the determinants of early blood pressure (BP) control associated with monotherapy in hypertensive individuals being managed in the primary care setting. The Valsartan Intensified Primary Care Reduction of Blood Pressure (VIPER-BP) study, was a multicenter, randomized controlled trial of an intensive approach to BP management. During a standardized run-in, 2185 participants commenced monotherapy (valsartan 80 mg/d) for 14 to 28 days. A total of 1978 participants aged 59±12 years (60% men) completed the run-in phase. Of these, 15.1%, 43.5%, and 41.4% participants had an initial BP target of ≤125/75, 130/80, and 140/90 mm Hg, respectively. A total of 416 of 2185 participants (19.0%) subsequently achieved their individual BP target during run-in with a mean BP change of -22.6±12.1/-12.9±8.2 mm Hg vs -4.2±16.2/-3.0±9.6 mm Hg for the rest (P<.001). These early responders were more likely to be women (adjusted odds ratio, 1.41; 95% confidence interval, 1.10-1.80), had lower BP at baseline, were less likely to have been treated previously (or for less time), and had a less stringent BP target. An initial period of monotherapy achieved BP control in a high proportion of hypertensive individuals with key groups (including women and de novo cases) more likely to show an early BP response.

Judging whether a patient is actually improving: more pitfalls from the science of human perception

Fallible human judgment may lead clinicians to make mistakes when assessing whether a patient is improving following treatment. This article provides a narrative review of selected studies in psychology that describe errors that potentially apply when a physician assesses a patient's response to treatment. Comprehension may be distorted by subjective preconceptions (lack of double blinding). Recall may fail through memory lapses (unwanted forgetfulness) and tacit assumptions (automatic imputation). Evaluations may be further compromised due to the effects of random chance (regression to the mean). Expression may be swayed by unjustified overconfidence following conformist groupthink (group polarization). An awareness of these five pitfalls may help clinicians avoid some errors in medical care when determining whether a patient is improving.

Course of untreated high blood pressure in the emergency department

Introduction

No clear understanding exists about the course of a patient's blood pressure (BP) during an emergency department (ED) visit. Prior investigations have demonstrated that BP can be reduced by removing patients from treatment areas or by placing patients supine and observing them for several hours. However, modern EDs are chaotic and noisy places where patients and their families wait for long periods in an unfamiliar environment. We sought to determine the stability of repeated BP measurements in the ED environment.

Methods

A prospective study was performed at an urban ED. Research assistants trained and certified in BP measurement obtained sequential manual BPs and heart rates on a convenience sample of 76 patients, beginning with the patient arrival in the ED. Patients were observed through their stay for up to 2 hours, and BP was measured at 10-minute intervals. Data analysis with SAS PROC MIXED (SAS Institute, Cary, North Carolina) for regression models with correlated data determined the shape of the curve as BP changed over time. Patients were grouped on the basis of their presenting BP as normal (less than 140/90), elevated (140–160/90–100), or severely elevated (greater than 160/100) for the regression analysis.

Results

A statistically significant downward trend in systolic and diastolic BP was observed only for those patients presenting with severely elevated BPs (ie, greater than 160/100).

Conclusion

We demonstrate a statistically significant decline in systolic and diastolic BP over time spent in the ED only for patients with severely elevated presenting BPs.

Severe acute hypertension among inpatients admitted from the emergency department

BACKGROUND

Hospitalists often treat patients with severe acute hypertension (AH) presenting to the hospital. Little is known about the epidemiology of this syndrome.

OBJECTIVE

To examine the prevalence of severe AH in patients admitted through the emergency department (ED) and its associated outcomes.

DESIGN

A cohort study using retrospectively collected vital signs and other clinical data.

PATIENTS

A total of 1,290,804 adults admitted between 2005 and 2007.

SETTING

One hundred fourteen acute-care hospitals.

MEASUREMENTS

Severe AH was defined as at least 1 systolic blood pressure (SBP) >180 mmHg. We used multivariable regression to estimate AH-attributable in-hospital mortality, need for mechanical ventilation (MV), and length of stay (LOS).

RESULTS

Severe AH occurred in 178,131 (13.8%) patients. Disease categories with the highest prevalence were nervous (29.0%), circulatory (16.0%), endocrine (14.7%), and kidney/urinary (13.5%). The overall in-hospital mortality was 3.6%. The relationship between severe AH strata and mortality was graded for nervous system diseases; mortality rates for each 10 mmHg increase in SBP from 180 to >220 mmHg were 6.5%, 8.1%, 9.9%, 12.0%, and 19.7%, respectively (P < 0.0001). The relationship between severe AH strata and need for MV was graded in the most pronounced way in respiratory and circulatory conditions (P < 0.0001). The relationship between severe AH strata and LOS was graded in most disease categories (P < 0.0001).

CONCLUSIONS

Severe AH appears common and its prevalence varies by underlying clinical condition. Severe AH is associated with excess in-hospital mortality for patients with nervous system diseases and, for most disease categories, prolongs hospitalization.

Asymptomatic hypertension in the emergency department: a matter of critical public health importance

Asymptomatic hypertension (HTN) is commonly encountered in the emergency department (ED), but in most circumstances little is done about it. While many factors may contribute to this, the failure to recognize asymptomatic HTN as a public health problem is particularly important. Given the established long-term consequences of elevated blood pressure (BP), a reconsideration of methods that could enhance surveillance and intervention in the ED is needed. In this article, we discuss the relevant epidemiology of asymptomatic HTN and present a novel approach using a modified version of the Haddon's matrix to systematically address the challenges that contribute to ineffective screening and suboptimal outcomes.

Provider self-report and practice: reassessment and referral of emergency department patients with elevated blood pressure

BACKGROUND

We attempted to identify patient factors associated with blood pressure (BP) reassessment and to compare health-care provider self-reported reassessment and referral to actual practice in an emergency department (ED) setting.

METHODS

Provider reassessment and referral practices were determined through systematic review of 1,250 medical records at five EDs. Medical records were included if patients were > or =18 years, nonpregnant, presented with a systolic (SBP) > or =140 or diastolic BP (DBP) > or =90 mm Hg, and discharged. A separate questionnaire obtained self-reported practice patterns of health-care providers. Multivariate logistic regression identified factors associated with patient BP reassessment and referral.

RESULTS

Of 1,250 patients, only 57% underwent BP reassessment and 9% received a referral for outpatient management. The most significant independent variables related to a reassessment were as follows: treatment of elevated BP in the ED (odds ratio (OR): 6.05; 95% confidence interval (CI): 1.80-20.31), chest pain (OR: 3.90; 95% CI: 2.37-6.42), and presence of an ED reassessment protocol (OR: 2.49; 95% CI: 1.77-3.50). The most significant factors associated with a referral included treatment of elevated BP in the ED (OR: 5.55; 95% CI: 2.72-11.32), presence of a reassessment protocol (OR: 2.58; 95% CI: 1.32-5.05), and a BP reassessment (OR: 2.56; 95% CI: 1.34-4.89). For self-reported practice patterns, 379 (72%) health-care providers completed questionnaires. Providers consistently overestimated their referral practices, yet the mean referral threshold values reported (SBP, 150 mm Hg; DBP, 93 mm Hg) were lower than the mean BP values of patients who actually received a directed referral (SBP, 170 mm Hg; DBP, 97 mm Hg, P < 0.0001).

CONCLUSIONS

Reassessment and referral of discharged ED patients with elevated BP was infrequent and health-care providers overestimate their reassessment and referral efforts.

Asymptomatically elevated blood pressure in the emergency department: a finding deserving of attention by emergency physicians?

The Emergency Department (ED) may be an ideal place to screen and refer patients for blood pressure monitoring in the outpatient setting. Yet, little is known about the public health significance of asymptomatically elevated blood pressure measurements in the ED and what to tell patients when these abnormal vital signs are recorded. Since the prevalence of hypertension and inadequately treated hypertension is so high, the incidental finding of elevated blood pressure in a previously undiagnosed patient may be a pivotal moment in that patient's life. For those patients carrying the diagnosis of hypertension, it is the author's opinion that the observation of elevated blood pressures should trigger advice to see their physicians to consider medication adjustments or changes. Emergency Physicians and their staff are in a unique position to screen and refer large populations of patients to their community physicians and help abort the long-term sequelae of unidentified or inadequately managed hypertension. How best to advise physicians and their patients requires research and innovative methods for transmitting important information to patients that may be unrelated to their primary complaint in the ED.

Severe Hypertension in the Geriatric Patient—Is it an Emergency or Not?

Hypertension is a medical condition commonly seen in the outpatient setting. Primary care providers should be aware that asymptomatic hypertension, despite the degree of elevation, is rarely an emergency. Based on consensus guidelines from the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure and the lack of any evidence showing harm, extreme blood pressure elevations do not need acute treatment. This article provides evidence for the argument that hypertension is rarely an emergency at all; even patients who have exceedingly high blood pressure can be treated as outpatients.

Recognizing asymptomatic elevated blood pressure in ED patients: how good (bad) are we?

OBJECTIVE

This study was conducted to determine if emergency medicine (EM) physicians recognize emergency department (ED) patients with asymptomatic elevated blood pressure (AEBP) by diagnosis, treatment, or referral. The study also evaluated whether differences exist in identification of AEBP based on patient age, sex, race, or insurance status.

METHODS

A retrospective chart review of all adult patients presenting to a tertiary care teaching hospital ED between April 1, 2004, and June 30, 2004, was performed. Patients were included if documented blood pressure(s) were 140/90 mm Hg or higher. Exclusion criteria included age younger than 18 years or older than 89 years, history of hypertension, admission, condition clearly defined by a hypertensive state, or blood pressure lower than 140/90 mm Hg.

RESULTS

A total of 9805 charts were reviewed; 1574 (16%) patients met inclusion criteria. The average age of our study patient was 38 +/- 14 years; 51% were women and 71.8% were African American. Only 112 patients with AEBP (7%) received attention for their elevated blood pressure (ie, diagnosis, treatment, medication prescription, and/or referral). There was no statistically significant difference between patients identified with AEBP and those not recognized by ED physicians by patient age, sex, race, or insurance status.

CONCLUSIONS

Emergency department physicians recognize, treat, and/or refer only a small percentage of ED patients with AEBP. No difference in identification, treatment, or referral exists based on patient age, sex, race, or insurance status.

Hypertensive emergency and severe hypertension: what to treat, who to treat, and how to treat

Remember to treat patients, not numbers. Use fast acting shortterm medicines only when convincing evidence of rapidly evolving end-organ damage is present. For all patients, emergent or asymptomatic, the treatment goal is long-term control of hypertension. Potent IV agents for the im-mediate control of elevated blood pressure need to be used cautiously,bearing in mind both the side effects and the hazards of overly rapid control of hypertension. Conventional oral medication regimens demonstrated to modify the risks of chronic hypertension should be used whenever possible and as early as is practical to promote gradual control of hypertension. Whenever a patient presents for the evaluation of severe hypertension in an emergent setting, take the opportunity to encourage appropriate ongoing follow-up; after all, hypertension is not a single episode, it is an ongoing threat to good health.

Evaluation and Treatment of Patients With Severely Elevated Blood Pressure in Academic Emergency Departments: A Multicenter Study

STUDY OBJECTIVE

Current guidelines advise that emergency department (ED) patients with severely elevated blood pressure be evaluated for acute target organ damage, have their medical regimen adjusted, and be instructed to follow up promptly for reassessment. We examine factors associated with performance of recommended treatment of patients with severely elevated blood pressure.

METHODS

Observational study performed during 1 week at 4 urban, academic EDs. Severely elevated blood pressure was defined as systolic blood pressure greater than or equal to 180 mm Hg or diastolic blood pressure greater than or equal to 110 mm Hg on at least 1 measurement. ED staff were blinded to the study purpose. Demographics, presenting complaints, vital signs, tests ordered, medications administered, disposition, and discharge instructions were recorded, and associations were tested in bivariate analyses.

RESULTS

Severely elevated blood pressure was noted in 423 patients. Serum chemistry was obtained in 73% of patients, ECG in 53% of patients, chest radiograph in 46% of patients, urinalysis in 43% of patients, and funduscopy documented in 36% of patients. All studies were performed in 6% of patients and were associated with complaints of dyspnea (odds ratio [OR] 3.1; 95% confidence interval [CI] 1.1 to 8.7) and chest pain (OR 3.0; 95% CI 1.2 to 7.6). Oral antihypertensives were administered to 36% of patients and were associated with blood pressure-related complaints (OR 2.0 [1.2 to 3.3]), patient-suspected severely elevated blood pressure (OR 5.6, 95% CI 2.0 to 15.3), and being uninsured (OR 2.0; 95% CI 1.2 to 3.3). Intravenous antihypertensives were given to 4% of patients, associated only with chest pain (OR 3.2; 95% CI 1.1 to 9.5). Modification of antihypertensive regimen was documented in 19% of discharged patients and associated with patient-suspected severely elevated blood pressure (OR 5.5; 95% CI 2.5 to 12.2) and being uninsured (OR 1.8; 95% CI 1.1 to 2.9).

CONCLUSION

The majority of ED patients with severely elevated blood pressure do not receive the evaluation, medical regimen modification, and discharge instructions advised by current guidelines. Further study is necessary to determine whether these recommendations are appropriate in this setting.

Lack of relationship between hypertension-associated symptoms and blood pressure in hypertensive ED patients

A number of cardiopulmonary and neurological symptoms are presumed to be associated with hypertension. We examined the prevalence of these symptoms in ED patients with elevated blood pressure (BP) and studied the relationship between symptom prevalence and BP value. We enrolled consecutive adult ED patients with sustained BP elevation (systolic BP>or=140 mm Hg, diastolic BP>or=90 mm Hg). BP values were categorized according to Joint National Committee on Prevention, Evaluation, and Treatment of High Blood Pressure, 6th Report criteria. Elevated BP was noted in 551 (29%) of 1908 patients. Unprompted complaints of hypertension-associated symptoms were noted in 26%, and there was no association between BP category and complaints other than dyspnea. Symptom interviews were conducted in 294 (56%) patients; 68% of this subset noted >or=1 current hypertension-associated symptom with no relationship between symptom prevalence and BP category. We conclude that symptoms putatively associated with hypertension are common among ED patients with elevated BP, and their prevalence appears unrelated to BP value.

Undiagnosed Hypertension in the ED Setting—An Unrecognized Opportunity by Emergency Nurses

INTRODUCTION

Hypertension is often undiagnosed, untreated, undertreated, and poorly controlled. Many patients use the emergency department as their primary source of health care, and the emergency department represents an opportunity to identify undiagnosed hypertension. We sought to (1) identify the prevalence of elevated blood pressures in low-acuity patients and (2) describe the existing practice of reassessment, treatment, and referral of abnormal vital signs in these patients.

METHODS

We conducted a retrospective study of 88 ED patients at an academic medical center. All patients meeting Emergency Severity Index level 4 or 5 criteria (low acuity) were eligible. The following variables were recorded: triage level, medical history and medications, disposition, and all blood pressures. The investigators independently reviewed and reached consensus regarding the following outcome variables: the need for and actual treatment of elevated blood pressure, and the need for and referral for blood pressure recheck after discharge.

RESULTS

Thirty-seven patients (45%) had hypertension by definition on arrival. Systolic hypertension was more common. Ten of the patients (27%) with elevated blood pressures had documented rechecks prior to discharge in the emergency department, and only one patient was referred for follow-up. Twenty-seven out of 37 low-acuity patients (73%) who presented with elevated blood pressures had no documentation of the blood pressure being rechecked and no documentation of the patient being referred.

CONCLUSION

Our data suggest that important opportunities for education and follow-up of hypertension are being missed.

The validity of emergency department triage blood pressure measurements

OBJECTIVE

Automated blood pressure (ABP) devices are ubiquitous at emergency department (ED) triage. Previous studies failed to evaluate ABP devices against accepted reference standards or demonstrate triage readings as accurate reflections of blood pressure (BP). This study evaluated ED triage measurements made using an ABP device and assessed agreement between triage BP and BP taken under recommended conditions.

METHODS

A prospective study was conducted at an urban teaching hospital. Patients were enrolled by convenience sampling. Simultaneous automated and manual triage BPs were obtained using one BP cuff with a Y-tube connector. Research assistants were certified in obtaining manual BP as described by the British Hypertension Society (BHS). Patients were placed in a quiet setting, and manual BP was repeated by American Heart Association (AHA) standards. Data analysis was performed using methods described by Bland and Altman. The ABP device was assessed using Association for the Advancement of Medical Instrumentation (AAMI) and BHS criteria.

RESULTS

One hundred seventy-one patients were enrolled. Systolic BP (sBP) range was 81 to 218 mm Hg; diastolic BP (dBP) range was 43 to 130 mm Hg. Automated vs. manual sBP difference was 3.8 +/- 11.2 mm Hg (95% confidence interval [CI] = 2.1 to 5.4); dBP difference was 6.6 +/- 9.0 mm Hg (95% CI = -7.9 to -5.2). Manual triage BP vs. AHA standard SBP difference was 11.6 +/- 12.8 mm Hg (95% CI = 9.1 to 14.1); dBP difference was 9.9 +/- 10.4 mm Hg (95% CI = 7.9 to 12.0). The ABP device failed to meet AAMI criteria and received a BHS rating of "D." Poor operator technique and extraneous patient and operator movement appeared to hamper accuracy.

CONCLUSIONS

ABP triage measurements show significant discrepancies from a reference standard. Repeat measurements following AHA standards demonstrate significant decreases in the measured blood pressures.

Regression to the mean. A threat to exercise science?

Regression to the mean (RTM) can bias any investigation where the response to treatment is classified relative to initial values for a given variable without the use of an appropriate control group. The phenomenon and resulting errors of interpretation have been recognised by clinicians in a number of disciplines. The causes of RTM include both intra-individual variance and measurement error. The magnitude of RTM can be estimated quite simply, given a knowledge of intra- and inter-individual variance. RTM can be avoided by using a fully controlled experimental design. Difficulties can also be minimised by making duplicate measurements prior to the experimental manipulation, the first measurement serving for classification, and the second (with randomly distributed variance) allowing an assessment of the response to treatment. Less satisfactorily, surrogate measurements (for example, plasma volume for maximal oxygen intake [VO2(max)]) can assess the bias introduced by an initial non-random sorting of study participants. The impact of RTM on the design and interpretation of investigations has as yet received little consideration by exercise scientists and sports physicians. The response to training is often related to initial measurements of a dependent variable such as heart size, ST segmental depression, fitness or level of physical activity. In particular, analyses of this type have been adduced to support the belief that the response to aerobic training is inversely related to an individual's VO2(max). In fact, RTM may account for a major part of this apparent relationship.

Nonparametric regression to the mean

Available data may reflect a true but unknown random variable of interest plus an additive error, which is a nuisance. The problem in predicting the unknown random variable arises in many applied situations where measurements are contaminated with errors; it is known as the regression-to-the-mean problem. There exists a well known solution when both the distributions of the true underlying random variable and the contaminating errors are normal. This solution is given by the classical regression-to-the-mean formula, which has a data-shrinkage interpretation. We discuss the extension of this solution to cases where one or both of these distributions are unknown and demonstrate that the fully nonparametric case can be solved for the case of small contaminating errors. The resulting nonparametric regression-to-the-mean paradigm can be implemented by a straightforward data-sharpening algorithm that is based on local sample means. Asymptotic justifications and practical illustrations are provided.

Severely increased blood pressure in the emergency department

Patients with severely increased blood pressure often present to the emergency department. Emergency physicians evaluate and treat hypertension in various contexts, ranging from the compliant patient with well-controlled blood pressure to the asymptomatic patient with increased blood pressure to the critically ill patient with increased blood pressure and acute target-organ deterioration. Despite extensive study and national guidelines for the assessment and treatment of chronically increased blood pressure, there is no clear consensus on the acute management of patients with severely increased blood pressure. In this article, we examine the broad spectrum of disease, from the asymptomatic to critically ill patient, and the dilemma it creates for the emergency physician in deciding how and when in the process to intervene.