Sources of inaccuracy in the measurement of adult patients' resting blood pressure in clinical settings: a systematic review

Blood Pressure Assessment in Adults in Clinical Practice and Clinic-Based Research: JACC Scientific Expert Panel

The accurate measurement of blood pressure (BP) is essential for the diagnosis and management of hypertension. Restricted use of mercury devices, increased use of oscillometric devices, discrepancies between clinic and out-of-clinic BP, and concerns about measurement error with manual BP measurement techniques have resulted in uncertainty for clinicians and researchers. The National Heart, Lung, and Blood Institute of the U.S. National Institutes of Health convened a working group of clinicians and researchers in October 2017 to review data on BP assessment among adults in clinical practice and clinic-based research. In this report, the authors review the topics discussed during a 2-day meeting including the current state of knowledge on BP assessment in clinical practice and clinic-based research, knowledge gaps pertaining to current BP assessment methods, research and clinical needs to improve BP assessment, and the strengths and limitations of using BP obtained in clinical practice for research and quality improvement activities.

Clinical Implementation of Self-Measured Blood Pressure Monitoring, 2015-2016

INTRODUCTION

Self-measured blood pressure monitoring (SMBP) plus additional clinical support is an evidence-based strategy that improves blood pressure control. Despite national recommendations for SMBP use and potential cost savings, insurance coverage for implementation is limited in the U.S. and little is known regarding clinical implementation.

METHODS

In 2017, using 2015 and 2016 DocStyles survey data from 1,590 primary care physicians and nurse practitioners in U.S. outpatient facilities, SMBP-related clinical practices and provider roles were assessed.

RESULTS

Almost all (97%) respondents reported using SMBP. Among 1,539 who used SMBP, more than half (60%) used SMBP for a combination of diagnostic and treatment purposes, whereas 24% used SMBP for diagnosis only and 16% used SMBP for treatment only. The most common methods for patients to share SMBP results with clinical staff were paper log (68%); during appointments (66%); by telephone (37%); by secure website (22%); or by secure e-mail (19%). Nearly all (98%) respondents reported that medication adjustments were provided to patients based on SMBP readings. About 15% did not counsel patients regarding cuff size, and 8% did not validate patient devices. Only 13% of respondents reported having monitor loaner programs, and availability did not vary by the financial status of the patient population (p=0.59).

CONCLUSIONS

SMBP is used widely in outpatient facilities as reported in the survey, although provider roles and SMBP-related practices vary, and gaps exist regarding patient counseling, device validation, and loaner program availability. As part of efforts to improve hypertension control, healthcare professionals can promote increased use of best practices for SMBP, whereas insurers can implement standardization and support of SMBP.

Comparison of automated clinical and research blood pressure measurements: Implications for clinical practice and trial design

Discrepancies between clinic and research blood pressure (BP) measurements lead to uncertainties in translating hypertension management guidelines into practice. We assessed the concordance between standardized automated clinic BP, from a primary care clinic, and research BP, from a randomized trial conducted at the same site. Mean single-visit clinic BP was higher by 4.4/3.8 mm Hg (P = 0.007/<0.001). Concordance in systolic BP (SBP) improved with closer proximity of measurements (difference = 2.5 mm Hg, P = 0.21 for visits within 7 days), but not averaging across multiple visits (difference =5.1(9.2) mm Hg; P < 0.001). This discrepancy was greater among female participants. Clinic-based difference in SBP between two visits was more variable than research-based change (SD = 19.6 vs 14.0; P = 0.002); a 2-arm trial using clinic measurements would need 95% more participants to achieve comparable power. Implementation of a bundled standardization intervention decreased discrepancies between clinic and research BP, compared to prior reports. However, clinic measurements remained higher and more variable, suggesting treatment to research-based targets may lead to overtreatment and using clinic BP approximately halves power in trials.

Blood Pressure Control and Other Quality of Care Metrics for Patients with Obesity and Diabetes: A Population-Based Cohort Study

INTRODUCTION

There are no population-level estimates in the United States for achievement of blood pressure goals in patients with diabetes and hypertension by obesity weight class.

AIM

We sought to examine the relationship between the extent of obesity and the achievement of guideline-recommended blood pressure goals and other quality of care metrics among patients with diabetes.

METHODS

We conducted an observational population-based cohort study of electronic health data of three large health systems from 2010-2012 in rural, urban and suburban settings of 51,229 adults with diabetes. Outcomes were achievement of diabetes quality of care metrics: blood pressure, A1c, and LDL control, and A1c and LDL testing. Two blood pressure goals were examined given the recommendation for adults with diabetes of 130/80 mmHg from JNC7 and the recommendation of 140/90 mmHg from JNC8 in 2014.

RESULTS

Patients in obesity classes I, II, and III with diagnosed hypertension were less likely to achieve blood pressure control at both the 140/90 mmHg and 130/80 mmHg control levels. The patients from obesity class III had the lowest likelihood of achieving control at the 130/80 mmHg goal, and control was markedly worse for the 130/80 mmHg threshold in all weight classes. There were minimal to no differences by weight class in LDL and A1c control and LDL and A1c testing.

CONCLUSIONS

Although the cardiovascular risk for patients with obesity and diabetes is greater than for non-obese patients with diabetes, we found that patients with obesity are even further behind in achieving blood pressure control.

A Primer on the New Guideline for the Prevention, Detection, Evaluation, and Management of Hypertension

Hypertension is a leading risk factor for the development of cardiovascular disease. In 2017, the American College of Cardiology and the American Heart Association published a new guideline for the prevention, detection, evaluation, and management of hypertension. The guideline adjusts the clinical parameters for diagnosis and management of hypertension. In this article we summarize the updates and provide some background on these changes as they relate to nursing practice implications, with specific implications for women's health.

Prospective external validation of the Predicting Out-of-OFfice Blood Pressure (PROOF-BP) strategy for triaging ambulatory monitoring in the diagnosis and management of hypertension: observational cohort study

OBJECTIVE

To prospectively validate the Predicting Out-of-OFfice Blood Pressure (PROOF-BP) algorithm to triage patients with suspected high blood pressure for ambulatory blood pressure monitoring (ABPM) in routine clinical practice.

DESIGN

Prospective observational cohort study.

SETTING

10 primary care practices and one hospital in the UK.

PARTICIPANTS

887 consecutive patients aged 18 years or more referred for ABPM in routine clinical practice. All underwent ABPM and had the PROOF-BP applied.

MAIN OUTCOME MEASURES

The main outcome was the proportion of participants whose hypertensive status was correctly classified using the triaging strategy compared with the reference standard of daytime ABPM. Secondary outcomes were the sensitivity, specificity, and area under the receiver operator characteristic curve (AUROC) for detecting hypertension.

RESULTS

The mean age of participants was 52.8 (16.2) years. The triaging strategy correctly classified hypertensive status in 801 of the 887 participants (90%, 95% confidence interval 88% to 92%) and had a sensitivity of 97% (95% confidence interval 96% to 98%) and specificity of 76% (95% confidence interval 71% to 81%) for hypertension. The AUROC was 0.86 (95% confidence interval 0.84 to 0.89). Use of triaging, rather than uniform referral for ABPM in routine practice, would have resulted in 435 patients (49%, 46% to 52%) being referred for ABPM and the remainder managed on the basis of their clinic measurements. Of these, 69 (8%, 6% to 10%) would have received treatment deemed unnecessary had they received ABPM.

CONCLUSIONS

In a population of patients referred for ABPM, this new triaging approach accurately classified hypertensive status for most, with half the utilisation of ABPM compared with usual care. This triaging strategy can therefore be recommended for diagnosis or management of hypertension in patients where ABPM is being considered, particularly in settings with limited resources.

A Network Meta-Analysis Comparing Semaglutide Once-Weekly with Other GLP-1 Receptor Agonists in Japanese Patients with Type 2 Diabetes

INTRODUCTION

Semaglutide once-weekly (QW) is a novel glucagon-like peptide-1 (GLP-1) analogue administered at a 0.5 or 1.0 mg dose. In the absence of head-to-head trials between semaglutide QW and other GLP-1 receptor agonists (GLP-1 RAs) in a Japanese population, a network meta-analysis (NMA) was performed. The objective was to assess the relative efficacy and safety of semaglutide QW vs GLP-1 RAs in Japanese patients with type 2 diabetes (T2DM), with a specific focus on the comparison between semaglutide 0.5 mg QW and dulaglutide 0.75 mg QW.

METHODS

A systematic review (SR) and supplementary Japanese searches were conducted to identify trials of GLP-1 RAs in Japanese patients on diet and exercise, who have previously received 0-1 oral antidiabetic drugs (OADs). Data at 52-56 weeks were extracted for the following outcomes (feasible for analysis in an NMA): glycated hemoglobin (HbA_1c), fasting plasma glucose (FPG), weight, systolic blood pressure (SBP), and overall hypoglycemia. The data were synthesized using an NMA and a Bayesian framework.

RESULTS

Four trials, identified from the SR and Japanese-specific searches, were relevant for inclusion in the NMA. When compared to dulaglutide 0.75 mg QW, semaglutide 0.5 mg QW was shown to provide significant reductions in HbA_1c [- 0.61% (12.3 mmol/mol)], weight (- 1.45 kg), SBP (- 5.03 mmHg), and FPG (- 1.26 mmol/L). No significant differences in the proportion of patients achieving a HbA_1c level < 7% (53 mmol/mol) or the risk of overall hypoglycemia were observed between semaglutide 0.5 mg QW and dulaglutide 0.75 mg QW.

CONCLUSION

Overall, semaglutide 0.5 mg QW was associated with significant reductions from baseline in HbA_1c, weight, SBP, and FPG compared with dulaglutide 0.75 mg QW in Japanese patients with T2DM. These data may provide valuable evidence for clinical decision-making, cost-effectiveness analyses, and health technology appraisal (HTA) requirements.

FUNDING

Novo Nordisk Pharma Ltd.

The role of clinic blood pressure for the diagnosis of hypertension

PURPOSE OF REVIEW

Recent data from randomized clinical trials and updates to hypertension guidelines warrant a review of the literature for the diagnosis and management of hypertension in the clinic setting. Although there have been significant advances in ambulatory blood pressure (BP) monitoring and home BP monitoring, office BP (OBP) measurements remains the primary means of diagnosis and treatment.

RECENT FINDINGS

The current review focuses on updated guidelines, proper technique, device selection, and the recent controversy regarding unattended BP measurements. We review the data on cardiovascular outcomes, the comparison of OBP with ambulatory BP monitoring and home BP monitoring and some of the pitfalls of OBP measurements.

SUMMARY

The current review highlights the need for constant review of BP goals to minimize cardiovascular risk and some of the ongoing controversies regarding OBP measurements.

Diagnostic precision of mentally estimated home blood pressure means

CONTEXT

Paper home blood pressure (HBP) charts are commonly brought to physicians at office visits. The precision and accuracy of mental calculations of blood pressure (BP) means are not known.

METHODS

A total of 109 hypertensive patients were instructed to measure and record their HBP for 1 week and to bring their paper charts to their office visit. Study section 1: HBP means were calculated electronically and compared to corresponding in-office BP estimates made by physicians. Study section 2: 100 randomly ordered HBP charts were re-examined repetitively by 11 evaluators. Each evaluator estimated BP means four times in 5, 15, 30, and 60 s (random order) allocated for the task. BP means and diagnostic performance (determination of therapeutic systolic and diastolic BP goals attained or not) were compared between physician estimates and electronically calculated results.

RESULTS

Overall, electronically and mentally calculated BP means were not different. Individual analysis showed that 83% of in-office physician estimates were within a 5-mmHg systolic BP range. There was diagnostic disagreement in 15% of cases. Performance improved consistently when the time allocated for BP estimation was increased from 5 to 15 s and from 15 to 30 s, but not when it exceeded 30 s.

CONCLUSION

Mentally calculating HBP means from paper charts can cause a number of diagnostic errors. Chart evaluation exceeding 30 s does not significantly improve accuracy. BP-measuring devices with modern analytical capacities could be useful to physicians.

Could self-measured office blood pressure be a hypertension screening tool for limited-resources settings?

Blood pressure (BP) was assessed by patients themselves in recently published trials. Self-measured office blood pressure (SMOBP) seems particularly interesting for limited health resources regions. The aim of our study was to evaluate the relationship between SMOBP values and those estimated by ambulatory blood pressure monitoring (ABPM). Six hundred seventy-seven patients were evaluated using both, SMOBP and ABPM. The differences between SMOBP and daytime ABPM were evaluated with paired "t" test. The correlations among SMOBP and ABPM were estimated using Pearson's r. The accuracy of SMOBP to identify abnormal ABPM was determined using area under ROC curve (AUC). Sensitivity, specificity, and positive and negative predictive values were calculated for different SMOBP cut-points. Using the average of three readings, systolic SMOBP was higher (3.7 (14.2) mmHg, p < 0.001) and diastolic SMOBP lower (1.5 (8.1) mmHg, p < 0.001) than ABPM. Both BP estimates had a significant correlation, r = 0.67 and r = 0.75 (p < 0.01) for systolic and diastolic BP, respectively. Systolic SMOBP predicted systolic abnormal ABPM; the AUC were 0.80 (0.77-0.84) and 0.78 (0.74-0.81) for daytime and 24 h hypertension, respectively. Diastolic SMOBP predicted diastolic hypertension, AUC 0.86 (0.83-0.88) for both daytime and 24 h hypertension. Neither correlations nor AUCs improved significantly using the average of five readings. SMOBP ≥ 160/90 mmHg was highly specific (>95%) to identify individuals with hypertension in the ABPM; SMOBP < 130/80 mmHg reasonably discarded abnormal ABPM. In conclusion, a high proportion of individuals could be classified adequately using SMOBP, reducing the necessity of healthcare resources and supporting its utility for screening purposes.

The Effect of Acute Consumption of Energy Drinks on Blood Pressure, Heart Rate and Blood Glucose in the Group of Young Adults

Background: Energy drinks (EDs) are very popular among young people, who consume them for various reasons. A standard ED typically contains 80 mg of caffeine, as well as glucose, taurine, vitamins and other ingredients. Excessive consumption of EDs and accumulation of the above ingredients, as well as their mutual interactions, can be hazardous to the health of young adults. The purpose of this study was to assess the effect of acute consumption of energy drinks on blood pressure, heart rate and blood glucose. Methods: The study involved 68 volunteers, healthy young adults (mean age 25 years), who were divided into two groups: the first consumed three EDs at one-hour intervals, and the second drank the same amount of water. All participants had their blood pressure (BP)—systolic and diastolic (SBP and DBP)—as well as heart rate (HR) and blood glucose (BG) measured. In addition, participants could report any health problems before and after consuming each portion of ED. Results: In the above experiment, having consumed three portions of ED (240 mg of caffeine), the participants presented a significant increase in DBP (p = 0.003), by over 8%, which coincided with a lack of any significant impact on SBP (p = 0.809). No significant changes were noted in HR (p = 0.750). Consumption of EDs caused a significant increase (p < 0.001) in BG, by ca. 21%, on average. Some participants reported various discomforts, which escalated after 2 and 3 EDs. Conclusions: Acute consumption of EDs contributed to increased diastolic blood pressure, blood glucose and level of discomfort in healthy young people. Our results reinforce the need for further studies on a larger population to provide sufficient evidence.

Hypertension Canada's 2018 Guidelines for Diagnosis, Risk Assessment, Prevention, and Treatment of Hypertension in Adults and Children

Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension in adults and children. This year, the adult and pediatric guidelines are combined in one document. The new 2018 pregnancy-specific hypertension guidelines are published separately. For 2018, 5 new guidelines are introduced, and 1 existing guideline on the blood pressure thresholds and targets in the setting of thrombolysis for acute ischemic stroke is revised. The use of validated wrist devices for the estimation of blood pressure in individuals with large arm circumference is now included. Guidance is provided for the follow-up measurements of blood pressure, with the use of standardized methods and electronic (oscillometric) upper arm devices in individuals with hypertension, and either ambulatory blood pressure monitoring or home blood pressure monitoring in individuals with white coat effect. We specify that all individuals with hypertension should have an assessment of global cardiovascular risk to promote health behaviours that lower blood pressure. Finally, an angiotensin receptor-neprilysin inhibitor combination should be used in place of either an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in individuals with heart failure (with ejection fraction < 40%) who are symptomatic despite appropriate doses of guideline-directed heart failure therapies. The specific evidence and rationale underlying each of these guidelines are discussed.

The impact of unrecorded readings on the precision and diagnostic performance of home blood pressure monitoring: a statistical study

Hypertension is a major cardiovascular risk factor. To address the disease adequately, most clinicians rely on home blood pressure monitoring (HBPM). However, the impact of unrecorded BP values on the precision and diagnostic performance of BP schedules is unknown. We obtained 103 HBP patients schedules from a previous study. Then, readings were randomly removed from each schedule in order to create new incomplete schedules using a resampling technique. We obtained 10,000 new incomplete schedules. For each number of randomly removed readings, the percentages of incomplete schedules outside a systolic/diastolic blood pressure (SBP/DBP) range of 5/3 mmHg were calculated from the same complete patient's schedule. The sensitivity and specificity of incomplete HBPM schedules regarding BP control were also assessed. One hundred three HBPM schedules were analyzed. Mean patients' age was 67.9 ± 9.9 years. In non-diabetic patients, the mean BP of complete schedules' means was 131.9 ± 12.4/75.5 ± 10.5. In diabetic patients, the mean BP of complete schedules' means was 135.5 ± 14.0/73.4 ± 8.2 mmHg. When schedules were composed of 14 and 21 random measures, differences over 5 mmHg were seen in 2.6% and 0.1% of non-diabetic patients' schedule and 3.7% and 0.1% of diabetic patients' schedule, respectively. At 21 measurements, sensitivity and specificity were approximately 95% and 98% in non-diabetic patients and 90% and 99% in non-diabetic patients, respectively. HBPM precision and diagnostic performance improve rapidly with accumulation of readings. Incomplete schedules composed of 21 readings can provide an almost perfect diagnostic tool compared with the complete schedule reference.

Are self-reported telemonitored blood pressure readings affected by end-digit preference: a prospective cohort study in Scotland

OBJECTIVE

Simple forms of blood pressure (BP) telemonitoring require patients to text readings to central servers creating an opportunity for both entry error and manipulation. We wished to determine if there was an apparent preference for particular end digits and entries which were just below target BPs which might suggest evidence of data manipulation.

DESIGN

Prospective cohort study SETTING: 37 socioeconomically diverse primary care practices from South East Scotland.

PARTICIPANTS

Patients were recruited with hypertension to a telemonitoring service in which patients submitted home BP readings by manually transcribing the measurements into text messages for transmission ('patient-texted system'). These readings were compared with those from primary care patients with uncontrolled hypertension using a system in which readings were automatically transmitted, eliminating the possibility of manipulation of values ('automatic-transmission system').

METHODS

A generalised estimating equations method was used to compare BP readings between the patient-texted and automatic-transmission systems, while taking into account clustering of readings within patients.

RESULTS

A total of 44 150 BP readings were analysed on 1068 patients using the patient-texted system compared with 20 705 readings on 199 patients using the automatic-transmission system. Compared with the automatic-transmission data, the patient-texted data showed a significantly higher proportion of occurrences of both systolic and diastolic BP having a zero end digit (OR 2.1, 95% CI 1.7 to 2.6) although incidence was <2% of readings. Similarly, there was a preference for systolic 134 and diastolic 84 (the threshold for alerts was 135/85) (134 systolic BP OR 1.5, 95% CI 1.3 to 1.8; 84 diastolic BP OR 1.5, 95% CI 1.3 to 1.9).

CONCLUSION

End-digit preference for zero numbers and specific-value preference for readings just below the alert threshold exist among patients in self-reporting their BP using telemonitoring. However, the proportion of readings affected is small and unlikely to be clinically important.

TRIAL REGISTRATION NUMBER

ISRCTN72614272; Post-results.

A bundled quality improvement program to standardize clinical blood pressure measurement in primary care

We evaluated use of a program to improve blood pressure measurement at 6 primary care clinics over a 6-month period. The program consisted of automated devices, clinical training, and support for systems change. Unannounced audits and electronic medical records provided evaluation data. Clinics used devices in 81.0% of encounters and used them as intended in 71.6% of encounters, but implementation fidelity varied. Intervention site systolic and diastolic blood pressure with terminal digit "0" decreased from 32.1% and 33.7% to 11.1% and 11.3%, respectively. Improvement occurred uniformly, regardless of sites' adherence to the measurement protocol. Providers rechecked blood pressure measurements less often post-intervention (from 23.5% to 8.1% of visits overall). Providers at sites with high protocol adherence were less likely to recheck measurements than those at low adherence sites. Comparison sites exhibited no change in terminal digit preference or repeat measurements. This study demonstrates that clinics can apply a pragmatic intervention to improve blood pressure measurement. Additional refinement may improve implementation fidelity.

Cardiovascular risk profiles in a lupus cohort: what do different calculators tell us?

Background

Cardiovascular disease (CVD) is the leading cause of death worldwide and this risk is increased in patients with SLE who may not conform to traditional cardiovascular risk profiles.

Aims

To determine the prevalence of high CVD risk among patients with SLE calculated using different risk calculators, and to characterise those identified as high risk.

Methods

A cross-sectional analysis to estimate CVD risk using the Framingham Risk Equation (Framingham score) and an SLE-specific CVD risk equation (SLE score) was undertaken using data from a single centre cohort. The characteristics of patients identified as 'high risk' by the SLE score only (the 'missed group') were compared with those identified by the Framingham score (the 'conventional group').

Results

146 patients were included; 22 (15%) and 44 (30%) were determined to be at 'high risk' based on the Framingham and SLE scores, respectively. Patients in the 'missed group' were less likely to have traditional risk factors and were more likely to be female (81% vs 50%; p=0.03), younger (mean age 54 vs 69 years p<0.01) and have lower systolic blood pressure (132 vs 143 mm Hg; p=0.05). Of those deemed high risk, only a minority were treated to target blood pressure and lipid levels.

Conclusions

A large proportion of patients with SLE could be re-classified as high risk using a formula that incorporates SLE disease-related parameters. These patients have different profiles to those identified using a conventional risk model. Optimal CVD risk assessment and management warrants further attention in SLE.

The effects of awareness and count duration on adult respiratory rate measurements: An experimental study

AIMS AND OBJECTIVES

To investigate whether awareness of manual respiratory rate monitoring affects respiratory rate in adults, and whether count duration influences respiratory rate estimates.

BACKGROUND

Nursing textbooks typically suggest that the patient should ideally be unaware of respiratory rate observations; however, there is little published evidence of the effect of awareness on respiratory rate, and none specific to manual measurement. In addition, recommendations about the length of the respiratory rate count vary from text to text, and the relevant empirical evidence is scant, inconsistent and subject to substantial methodological limitations.

DESIGN

Experimental study with awareness of respiration monitoring (aware, unaware; randomised between-subjects) and count duration (60 s, 30 s, 15 s; within-subjects) as the independent variables. Respiratory rate (breaths/minute) was the dependent variable.

METHODS

Eighty-two adult volunteers were randomly assigned to aware and unaware conditions. In the baseline block, no live monitoring occurred. In the subsequent experimental block, the researcher informed aware participants that their respiratory rate would be counted, and did so. Respirations were captured throughout via video recording, and counted by blind raters viewing 60-, 30- and 15-s extracts. The data were collected in 2015.

RESULTS

There was no baseline difference between the groups. During the experimental block, the respiratory rates of participants in the aware condition were an average of 2.13 breaths/minute lower compared to unaware participants. Reducing the count duration from 1 min to 15 s caused respiratory rate to be underestimated by an average of 2.19 breaths/minute (and 0.95 breaths/minute for 30-s counts). The awareness effect did not depend on count duration.

CONCLUSIONS

Awareness of monitoring appears to reduce respiratory rate, and shorter monitoring durations yield systematically lower respiratory rate estimates.

RELEVANCE TO CLINICAL PRACTICE

When interpreting and acting upon respiratory rate data, clinicians should consider the potential influence of these factors, including cumulative effects.