Validation of the Stabil-O-Graph blood pressure self-measurement device

Relationship of Blood Pressure, Health Behaviors, and New Diagnosis and Control of Hypertension in the BP-CHECK Study

BACKGROUND

Undiagnosed hypertension and uncontrolled blood pressure (BP) are common and contribute to excess cardiovascular morbidity and mortality. We examined whether BP control, changes in BP, and patient behaviors and attitudes were associated with a new hypertension diagnosis.

METHODS

We performed a post hoc analysis of 323 participants from BP-CHECK (Blood Pressure Checks for Diagnosing Hypertension), a randomized diagnostic study of BP measuring methods in adults without diagnosed hypertension with elevated BP recruited from 12 primary care clinics of an integrated health care system in Washington State during 2017 to 2019. All 323 participants returned a positive diagnostic test for hypertension based on 24-hour ambulatory BP monitoring and were followed for 6 months. We used linear regression to examine the relationships between a new hypertension diagnosis (primary independent variable) and differences in the change in study outcomes from baseline to 6-month.

RESULTS

Mean age of study participants was 58.3 years (SD, 13.1), 147 (45%) were women, and 253 (80%) were of non-Hispanic White race. At 6 months, 154 of 323 (48%) participants had a new hypertension diagnosis of whom 88 achieved target BP control. Participants with a new hypertension diagnosis experienced significantly larger declines from baseline in BP (adjusted mean difference: systolic BP, -7.6 mm Hg [95% CI, -10.3 to -4.8]; diastolic BP, -3.8 mm Hg [95% CI, -5.6 to -2.0]) compared with undiagnosed peers. They were also significantly more likely to achieve BP control by 6 months compared with undiagnosed participants (adjusted relative risk, 1.5 [95% CI, 1.1 to 2.0]). At 6 months, 101 of 323 participants (31%) with a positive ambulatory BP monitoring diagnostic test remained with undiagnosed hypertension, uncontrolled BP, and no antihypertensive medications.

CONCLUSIONS

Approximately one-third of participants with high BP on screening and ambulatory BP monitoring diagnostic testing remained with undiagnosed hypertension, uncontrolled BP, and no antihypertensive medications after 6 months. New strategies are needed to enhance integration of BP diagnostic testing into clinical practice.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03130257.

Is Hypertension Diagnostic Testing and Diagnosis Associated With Psychological Distress?

BACKGROUND

Psychological impacts of hypertension diagnostic testing and new hypertension diagnoses are unclear.

METHODS

BP-CHECK was a randomized diagnostic study conducted in 2017-2019 in an integrated healthcare system. Participants with no hypertension diagnosis or medications and elevated blood pressure (BP) were randomized to one of three diagnostic regimens: (i) Clinic, (ii) Home, or (iii) Kiosk. Participants completed questionnaires at baseline, after completion of the diagnostic regimens, and at 6 months. Outcomes included changes from baseline in health-related quality of life (HRQOL), BP-related worry, and thoughts about having a stroke or heart attack.

RESULTS

Participants (n = 482) were mostly over age 50 (77.0%), and White race (80.3%). HRQOL did not significantly change from baseline to 3 weeks or 6 months. Among all participants, BP-related worry and concerns about having a heart attack or stroke increased significantly from baseline to 3 weeks, with heart attack and stroke concerns significantly higher in the Kiosk compared Clinic and Home groups. At 6 months, thoughts about having a heart attack or stroke returned to baseline overall and in the Kiosk group, however BP-related worry was significantly higher among those with, compared to those without, a new hypertension diagnosis.

CONCLUSIONS

The hypertension diagnostic process did not lead to short-term or intermediate-term changes in self-reported HRQOL. However, BP-related worry increased short-term and persisted at 6 months among individuals with a new hypertension diagnosis. Results warrant validation in more representative populations and additional exploration of the impacts of this worry on psychological well-being and hypertension control.

CLINICALTRIALS.GOV IDENTIFIER

NCT03130257.

Acceptability and Adherence to Home, Kiosk, and Clinic Blood Pressure Measurement Compared to 24-H Ambulatory Monitoring

BACKGROUND

The US Preventive Services Task Force recommends measuring blood pressure (BP) outside of clinic/office settings. While various options are available, including home devices, BP kiosks, and 24-h ambulatory BP monitoring (ABPM), understanding patient acceptability and adherence is a critical factor for implementation.

OBJECTIVE

To compare the acceptability and adherence of clinic, home, kiosk, and ABPM measurement.

DESIGN

Comparative diagnostic accuracy study which randomized adults to one of three BP measurement arms: clinic, home, and kiosk. ABPM was conducted on all participants.

PARTICIPANTS

Adults (18-85 years) receiving care at 12 Kaiser Permanente Washington primary care clinics (Washington State, USA) with a high BP (≥ 138 mmHg systolic or ≥ 88 mmHg diastolic) in the electronic health record with no hypertension diagnosis and on no hypertensive medications and with high BP at a research screening visit.

MEASURES

Patient acceptability was measured using a validated survey which was used to calculate an overall acceptability score (range 1-7) at baseline, after completing their assigned BP measurement intervention, and after completing ABPM. Adherence was defined based on the pre-specified number of BP measurements completed.

KEY RESULTS

Five hundred ten participants were randomized (mean age 59 years), with mean BP of 150/88. Overall acceptability score was highest (i.e. most acceptable) for Home BP (mean 6.2, SD 0.7) and lowest (least acceptable) for ABPM (mean 5.0, SD 1.0); scores were intermediate for Clinic (5.5, SD 1.1) and Kiosk (5.4, SD 1.0). Adherence was higher for Home (154/170, 90.6%) and Clinic (150/172, 87.2%) than for Kiosk (114/168, 67.9%)). The majority of participants (467/510, 91.6%) were adherent to ABPM.

CONCLUSIONS

Participants found home BP measurement most acceptable followed by clinic, BP kiosks, and ABPM. Our findings, coupled with recent evidence regarding the accuracy of home BP measurement, further support the routine use of home-based BP measurement in primary care practice in the US.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03130257 https://clinicaltrials.gov/ct2/show/NCT03130257.

Clinic, Home, and Kiosk Blood Pressure Measurements for Diagnosing Hypertension: a Randomized Diagnostic Study

BACKGROUND

The US Preventive Services Task Force recommends blood pressure (BP) measurements using 24-h ambulatory monitoring (ABPM) or home BP monitoring before making a new hypertension diagnosis.

OBJECTIVE

Compare clinic-, home-, and kiosk-based BP measurement to ABPM for diagnosing hypertension.

DESIGN, SETTING, AND PARTICIPANTS

Diagnostic study in 12 Washington State primary care centers, with participants aged 18-85 years without diagnosed hypertension or prescribed antihypertensive medications, with elevated BP in clinic.

INTERVENTIONS

Randomization into one of three diagnostic regimens: (1) clinic (usual care follow-up BPs); (2) home (duplicate BPs twice daily for 5 days); or (3) kiosk (triplicate BPs on 3 days). All participants completed ABPM at 3 weeks.

MAIN MEASURES

Primary outcome was difference between ABPM daytime and clinic, home, and kiosk mean systolic BP. Differences in diastolic BP, sensitivity, and specificity were secondary outcomes.

KEY RESULTS

Five hundred ten participants (mean age 58.7 years, 80.2% white) with 434 (85.1%) included in primary analyses. Compared to daytime ABPM, adjusted mean differences in systolic BP were clinic (-4.7mmHg [95% confidence interval -7.3, -2.2]; P<.001); home (-0.1mmHg [-1.6, 1.5];P=.92); and kiosk (9.5mmHg [7.5, 11.6];P<.001). Differences for diastolic BP were clinic (-7.2mmHg [-8.8, -5.5]; P<.001); home (-0.4mmHg [-1.4, 0.7];P=.52); and kiosk (5.0mmHg [3.8, 6.2]; P<.001). Sensitivities for clinic, home, and kiosk compared to ABPM were 31.1% (95% confidence interval, 22.9, 40.6), 82.2% (73.8, 88.4), and 96.0% (90.0, 98.5), and specificities 79.5% (64.0, 89.4), 53.3% (38.9, 67.2), and 28.2% (16.4, 44.1), respectively.

LIMITATIONS

Single health care organization and limited race/ethnicity representation.

CONCLUSIONS

Compared to ABPM, mean BP was significantly lower for clinic, significantly higher for kiosk, and without significant differences for home. Clinic BP measurements had low sensitivity for detecting hypertension. Findings support utility of home BP monitoring for making a new diagnosis of hypertension.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03130257 https://clinicaltrials.gov/ct2/show/NCT03130257.

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.

Patient characteristics do not predict the individual response to antihypertensive medication: a cross-over trial

BACKGROUND

International guidelines on hypertension management do not agree on whether patient characteristics can be used for the first choice of treatment of uncomplicated essential hypertension.

OBJECTIVE

We wanted to identify predictive patient characteristics to the response of two different classes of antihypertensive drugs in patients with newly diagnosed hypertension in primary care.

METHODS

We conducted a prospective, open label, blinded endpoint cross-over trial in 120 patients with a new diagnosis of hypertension from 10 family practices. Patients received 4 weeks of 12.5 mgr hydrochlorothiazide once daily and 4 weeks of 80 mgr valsartan once daily, each followed by a 4-week washout. The sequence of drugs was randomized. Age, sex and menopausal state were recorded at run in and 24 h ambulatory blood pressure, office blood pressure, plasma renin concentration, NT-proBNP, potassium, estimated glomerular filtration rate, urinary albumin, body mass index and waist circumference at each regimen change. The difference in systolic blood pressure response between both study drugs, calculated from mean daytime ambulatory blood pressures, was the main outcome measure.

RESULTS

Ninety-eight patients (52% female; median age 53 years) were eligible for per-protocol-analysis. None of the studied variables were predictive for the difference in systolic blood pressure response. Individual systolic blood pressure responses ranged from an increase by 18 mmHg to a decrease of 39 mmHg.

CONCLUSION

In a relevant group of primary care patients with newly diagnosed hypertension, we were unable to detect predictors of treatment response. This study rather supports the United States and European guidelines than the United Kingdom and Dutch guidelines on hypertension.

Engineering a mobile health tool for resource-poor settings to assess and manage cardiovascular disease risk: SMARThealth study

BACKGROUND

The incidence of chronic diseases in low- and middle-income countries is rapidly increasing both in urban and rural regions. A major challenge for health systems globally is to develop innovative solutions for the prevention and control of these diseases. This paper discusses the development and pilot testing of SMARTHealth, a mobile-based, point-of-care Clinical Decision Support (CDS) tool to assess and manage cardiovascular disease (CVD) risk in resource-constrained settings. Through pilot testing, the preliminary acceptability, utility, and efficiency of the CDS tool was obtained.

METHODS

The CDS tool was part of an mHealth system comprising a mobile application that consisted of an evidence-based risk prediction and management algorithm, and a server-side electronic medical record system. Through an agile development process and user-centred design approach, key features of the mobile application that fitted the requirements of the end users and environment were obtained. A comprehensive analytics framework facilitated a data-driven approach to investigate four areas, namely, system efficiency, end-user variability, manual data entry errors, and usefulness of point-of-care management recommendations to the healthcare worker. A four-point Likert scale was used at the end of every risk assessment to gauge ease-of-use of the system.

RESULTS

The system was field-tested with eleven village healthcare workers and three Primary Health Centre doctors, who screened a total of 292 adults aged 40 years and above. 34% of participants screened by health workers were identified by the CDS tool to be high CVD risk and referred to a doctor. In-depth analysis of user interactions found the CDS tool feasible for use and easily integrable into the workflow of healthcare workers. Following completion of the pilot, further technical enhancements were implemented to improve uptake of the mHealth platform. It will then be evaluated for effectiveness and cost-effectiveness in a cluster randomized controlled trial involving 54 southern Indian villages and over 16000 individuals at high CVD risk.

CONCLUSIONS

An evidence-based CVD risk prediction and management tool was used to develop an mHealth platform in rural India for CVD screening and management with proper engagement of health care providers and local communities. With over a third of screened participants being high risk, there is a need to demonstrate the clinical impact of the mHealth platform so that it could contribute to improved CVD detection in high risk low resource settings.

Efficacy of a text messaging (SMS) based intervention for adults with hypertension: protocol for the StAR (SMS Text-message Adherence suppoRt trial) randomised controlled trial

Background

Interventions to support people with hypertension in attending clinics and taking their medication have potential to improve outcomes, but delivery on a wide scale and at low cost is challenging. Some trials evaluating clinical interventions using short message service (SMS) text-messaging systems have shown important outcomes, although evidence is limited. We have developed a novel SMS system integrated with clinical care for use by people with hypertension in a low-resource setting. We aim to test the efficacy of the system in improving blood pressure control and treatment adherence compared to usual care.

Methods/design

The SMS Text-message Adherence suppoRt trial (StAR) is a pragmatic individually randomised three-arm parallel group trial in adults treated for hypertension at a single primary care centre in Cape Town, South Africa. The intervention is a structured programme of clinic appointment, medication pick-up reminders, medication adherence support and hypertension-related education delivered remotely using an automated system with either informational or interactive SMS text-messages. Usual care is supplemented by infrequent non-hypertension related SMS text-messages. Participants are 1:1:1 individually randomised, to usual care or to one of the two active interventions using minimisation to dynamically adjust for gender, age, baseline systolic blood pressure, years with hypertension, and previous clinic attendance. The primary outcome is the change in mean systolic blood pressure at 12-month follow-up from baseline measured with research staff blinded to trial allocation. Secondary outcomes include the proportion of patients with 80% or more of days medication available, proportion of participants achieving a systolic blood pressure less than 140 mmHg and a diastolic blood pressure less than 90 mmHg, hospital admissions, health status, retention in clinical care, satisfaction with treatment and care, and patient related quality of life. Anonymised demographic data are collected on non-participants.

Discussion

The StAR trial uses a novel, low cost system based on widely available mobile phone technology to deliver the SMS-based intervention, manage communication with patients, and measure clinically relevant outcomes. The results will inform implementation and wider use of mobile phone based interventions for health care delivery in a low-resource setting.

Trial registration

NCT02019823

Telemonitoring-based service redesign for the management of uncontrolled hypertension (HITS): cost and cost-effectiveness analysis of a randomised controlled trial

OBJECTIVES

To compare the costs and cost-effectiveness of managing patients with uncontrolled blood pressure (BP) using telemonitoring versus usual care from the perspective of the National Health Service (NHS).

DESIGN

Within trial post hoc economic evaluation of data from a pragmatic randomised controlled trial using an intention-to-treat approach.

SETTING

20 socioeconomically diverse general practices in Lothian, Scotland.

PARTICIPANTS

401 primary care patients aged 29-95 with uncontrolled daytime ambulatory blood pressure (ABP) (≥135/85, but <210/135 mm Hg).

INTERVENTION

Participants were centrally randomised to 6 months of a telemonitoring service comprising of self-monitoring of BP transmitted to a secure website for review by the attending nurse/doctor and patient, with optional automated patient decision-support by text/email (n=200) or usual care (n-201). Randomisation was undertaken with minimisation for age, sex, family practice, use of three or more hypertension drugs and self-monitoring history.

MAIN OUTCOME MEASURES

Mean difference in total NHS costs between trial arms and blinded assessment of mean cost per 1 mm Hg systolic BP point reduced.

RESULTS

Home telemonitoring of BP costs significantly more than usual care (mean difference per patient £115.32 (95% CI £83.49 to £146.63; p<0.001)). Increased costs were due to telemonitoring service costs, patient training and additional general practitioner and nurse consultations. The mean cost of systolic BP reduction was £25.56/mm Hg (95% CI £16.06 to £46.89) per patient.

CONCLUSIONS

Over the 6-month trial period, supported telemonitoring was more effective at reducing BP than usual care but also more expensive. If clinical gains are maintained, these additional costs would be very likely to be compensated for by reductions in the cost of future cardiovascular events. Longer-term modelling of costs and outcomes is required to fully examine the cost-effectiveness implications.

TRIAL REGISTRATION

International Standard Randomised Controlled Trials, number ISRCTN72614272.

Telemonitoring based service redesign for the management of uncontrolled hypertension: multicentre randomised controlled trial

OBJECTIVE

To determine if an intervention consisting of telemonitoring and supervision by usual primary care clinicians of home self measured blood pressure and optional patient decision support leads to clinically important reductions in daytime systolic and diastolic ambulatory blood pressure in patients with uncontrolled blood pressure.

DESIGN

Multicentre randomised controlled trial.

SETTING

20 primary care practices in south east Scotland.

PARTICIPANTS

401 people aged 29-95 years with uncontrolled blood pressure (mean daytime ambulatory measurement ≥ 135/85 mm Hg but ≤ 210/135 mm Hg).

INTERVENTION

Self measurement and transmission of blood pressure readings to a secure website for review by the attending nurse or doctor and participant, with optional automated patient decision support by text or email for six months.

MAIN OUTCOME MEASURES

Blinded assessment of mean daytime systolic ambulatory blood pressure six months after randomisation.

RESULTS

200 participants were randomised to the intervention and 201 to usual care; primary outcome data were available for 90% of participants (182 and 177, respectively). The mean difference in daytime systolic ambulatory blood pressure adjusted for baseline and minimisation factors between intervention and usual care was 4.3 mm Hg (95% confidence interval 2.0 to 6.5; P=0.0002) and for daytime diastolic ambulatory blood pressure was 2.3 mm Hg (0.9 to 3.6; P=0.001), with higher values in the usual care group. The intervention was associated with a mean increase of one general practitioner (95% confidence interval 0.5 to 1.6; P=0.0002) and 0.6 (0.1 to 1.0; P=0.01) practice nurse consultations during the course of the study.

CONCLUSIONS

Supported self monitoring by telemonitoring is an effective method for achieving clinically important reductions in blood pressure in patients with uncontrolled hypertension in primary care settings. However, it was associated with increase in use of National Health Service resources. Further research is required to determine if the reduction in blood pressure is maintained in the longer term and if the intervention is cost effective.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN72614272.

Acute changes in pulse pressure in relation to constituents of particulate air pollution in elderly persons

An increased pulse pressure (difference between systolic and diastolic blood pressure) suggests aortic stiffening. The objective of this study was to examine the acute effects of both particulate matter (PM) mass and composition on blood pressure, among elderly persons. We carried out a panel study in persons living in elderly homes in Antwerp, Belgium. We recruited 88 non-smoking persons, 70% women with a mean age of 83 years (standard deviation: 5.2). Blood pressure was measured and a blood sample was collected on two time points, which were chosen so that there was an exposure contrast in ambient PM exposure. The elemental content of the collected indoor and outdoor PM(2.5) (particulate matter with an aerodynamic diameter <2.5 μm) mass concentration was measured. Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) on outdoor PM(10) (particulate matter with an aerodynamic diameter <10 μm) were measured. Each interquartile range increase of 20.8 μg/m³ in 24-h mean outdoor PM(2.5) was associated with an increase in pulse pressure of 4.0 mm Hg (95% confidence interval: 1.8-6.2), in persons taking antihypertensive medication (n=57), but not in persons not using antihypertensive medication (n=31) (p for interaction: 0.02). Vanadium, iron and nickel contents of PM(2.5) were significantly associated with systolic blood pressure and pulse pressure, among persons on antihypertensive medication. Similar results were found for indoor concentrations. Of the oxy-PAHs, chrysene-5,6-dione and benzo[a]pyrene-3,6-dione were significantly associated with increases in systolic blood pressure and pulse pressure. In elderly, pulse pressure was positively associated with acute increases in outdoor and indoor air pollution, among persons taking antihypertensive medication. These results might form a mechanistic pathway linking air pollution as a trigger of cardiovascular events.

Blood pressure and particulate air pollution in schoolchildren of Lahore, Pakistan

BACKGROUND

Air pollution is a growing health problem for urban populations in emerging economies. The present study examines the (cross-sectional) relation between blood pressure and particulate air pollution in schoolchildren of Lahore (Pakistan).

METHODS

We recruited a sample of 8-12 year-old children (mean age 9.9 years; 45% girls) from two schools in Lahore situated in areas with low (n = 79) and high (n = 100) air pollution, respectively. During the study period (January-April 2009) particulate pollution [PM(10) and PM(2.5) i.e. particles with aerodynamic diameters below 10 μm or 2.5 μm, respectively] was measured at the school sites with a laser operated device (Metone Aerocet 531). Blood pressure was measured, after 5 minutes of sitting rest, using an automated device (average of 5 consecutive measurements). Spot urine samples were also collected and concentrations of Na and K were measured.

RESULTS

Mean daily values of PM2.5 were 28.5 μg/m(3) (SD: 10.3) and 183 μg/m(3) (SD: 30.2), in the low and high pollution areas, respectively. Systolic and diastolic blood pressure were significantly higher in children living in the high pollution area (115.9/70.9 mm Hg) than in the low pollution area (108.3/66.4 mm Hg), independently of age, gender, height, weight, socio-economic status, passive smoking and the urinary concentrations of Na, K, and creatinine.

CONCLUSIONS

In 8-12 year-old children, exposure to (traffic-related) air pollution was associated with higher systolic and diastolic blood pressure. These findings, if they persist, might have clinical relevance at older age.

The relationship between hypertension and salt intake in Turkish population: SALTURK study

This population-based epidemiological study was aimed to evaluate the daily salt intake and its relation to blood pressure in a representative group of Turkish population. The enrolled normotensive and hypertensive individuals (n = 1970) completed a questionnaire including demographics, dietary habits, hypertension awareness and drug usage. Blood pressure was measured and to estimate salt consumption, 24-h urine samples were collected. The daily urinary sodium excretion was 308.3 ± 143.1 mmol/day, equal to a salt intake of 18.01 g/day. Salt intake was higher in obese participants, rural residents, participants with lower education levels and elderly. A positive linear correlation between salt intake and systolic and diastolic blood pressures was demonstrated (r = 0.450, p = 0.020; r = 0.406, p = 0.041; respectively), and each 100 mmol/day of salt intake resulted in 5.8 and 3.8 mmHg increase in systolic and diastolic blood pressures, respectively. Salt intake and systolic blood pressure was significantly correlated in normal weight individuals (r = 0.257, p < 0.01). The Turkish population consumes a great amount of salt; salt intake and blood pressure was positively correlated. Efforts in sodium restriction are therefore crucial in the management of hypertension as part of national and global health policies.

European Society of Hypertension International Protocol for the validation of blood pressure monitors: a critical review of its application and rationale for revision

OBJECTIVE

To perform a systematic review of validation studies of blood pressure measuring devices done using the European Society of Hypertension International Protocol (ESH-IP) since its publication in 2002.

METHODS

Major aspects of ESH-IP studies are described. A review of the ESH-IP performance, problems and violations in its application, and the effect of applying several more stringent validation criteria in an ESH-IP revision is carried out.

RESULTS

From January 2002 to June 2009, 104 validation studies had been conducted using the ESH-IP, 36 using the British Hypertension Society protocol and 28 using the US Association for the Advancement of Medical Instrumentation protocol. Among 78 studies reported up to June 2008, in 66 (85%) the tested device has passed the ESH-IP. In 19 validations a modification of the ESH-IP was performed to adapt for specific study needs (population or device). Protocol violations of the ESH-IP were identified in 23 studies (eight major violations). A test of several arbitrarily chosen changes in the ESH-IP validation criteria applied in the published studies showed the phase 2.1 criterion (BP differences < or =15 mmHg) and the phase 2.2 criteria to be the more stringent.

CONCLUSION

The ESH-IP has succeeded in expanding the validation procedure worldwide by three to four-fold compared with the period before its publication. There is a need for protocol revision aiming to address issues that appeared in published studies, prevent protocol violations, and ensure complete data reporting. Standardization of the ESH-IP validation studies' report and application of more stringent criteria should be considered.

Effect of an intensive nurse-managed medical care programme on ambulatory blood pressure in hypertensive patients

BACKGROUND

Uncontrolled hypertension is a major primary healthcare problem.

AIM

To investigate whether blood pressure (BP) control in primary care could be improved by nurses taking responsibility for managing hypertensive patients.

METHODS

Randomized trial with two groups: usual or intensive care. Patients diagnosed previously as hypertensive and with a systolic office BP greater than 140mmHg were randomized to an intensive care programme managed by trained nurses or to usual care. The intensive care programme included a visit every 6 weeks to the general practitioner's office, with standardized BP measurement, self-measurement training, risk factor checks and advice on BP reduction. The intervention lasted for 1 year. The primary endpoints were systolic BP obtained by 24-hour ambulatory BP monitoring after 1 year and the change compared with baseline.

RESULTS

Two hundred patients from 19 physicians were enrolled (102 in the intensive care group). Data on ambulatory BP were available from 140 patients. Systolic BP declined from 134.4+/-14.0 to 126.3+/-10.4mmHg in the intensive care group and from 132.4+/-13.5 to 128.2+/-13.0mmHg in the usual care group. There was no statistically significant difference in values after 1 year (p=0.332). The reduction in systolic BP was significantly greater in the intensive care group (7.6 vs 3.3mmHg in the usual care group; p=0.036). Similar results were observed for diastolic BP and day- and night-time measurements.

CONCLUSIONS

An intensive medical care programme in the office setting managed by trained nurses can improve BP control effectively. Nurses could take more responsibility for managing hypertensive patients.

Poor adherence to home blood pressure measurement schedule

BACKGROUND

Consensus dictates that devices used for home blood pressure (BP) measurement should be equipped with a memory to store readings, rather than trusting patients' logbooks. However, data entered in the memory rely on patients' adherence to measurement schedules. We investigated the number and relevance of deviations from the requested measurement schedule.

METHODS

We instructed 106 patients to perform 28 BP readings in a 2-week period with a memory-equipped electronic device. Patients were requested to note their scheduled BP values in their logbook and were not informed of the presence of a memory function.

RESULTS

The concordance between all BP recordings in both memory and logbook was 90.1% of possible total scheduled readings. The difference in mean BP of all readings from memory compared with all readings from the logbook was -0.06 mmHg (95% confidence interval -0.79 to 0.68) systolic and -0.28 mmHg (95% confidence interval -0.97 to 0.40) diastolic. Unscheduled measurements were performed by 57.5% of patients. Missing scheduled readings in both logbook and memory were found in 34.0% of patients. Fictional data were present for 16.0% of patients. When comparing all individual BP readings from the memory and the logbook, 10.4% of patients were classified in another hypertension stratum according to the European Society of Hypertension criteria. In 23.6% of patients, we did not find any bias.

CONCLUSION

In spite of the use of memory-equipped devices, to ensure patients' adherence to measurement schedules, patients still need proper instruction and a close watch.

The impact of pulse pressure on the accuracy of wrist blood pressure measurement

There is an increasing number of wrist blood pressure measurement devices that successfully passed the validation procedures of the British Hypertension Society (BHS) and the European Society of Hypertension (ESH). It remains unknown, however, whether pulse pressure as a marker of arterial stiffness and vascular ageing affects the accuracy of these devices. An ESH protocol validated wrist device was compared with the upper arm mercury sphygmomanometry in a study population (33 patients, 99 measurements) including a relevant number of subjects with pulse pressure >50 mm Hg (84.8%) and isolated systolic hypertension (27.3%). Mean systolic bias was 10.2 mm Hg with 95% limits of agreement of -13.1 and 33.6 mm Hg, mean diastolic bias was 4.8 mm Hg with limits of agreement of -11.0 and 20.7 mm Hg. The impact of body mass index, age, systolic blood pressure and pulse pressure on the absolute value of blood pressure bias was tested by stepwise multiple regression analysis. The systolic bias significantly depended on pulse pressure, whereas there was no significant effect of the independent variables on the diastolic bias. Separate correlation analysis showed a significant correlation between pulse pressure and both absolute systolic bias (Pearson r=0.48, P<0.001) and relative systolic bias (systolic bias divided by systolic blood pressure, Pearson r=0.29, P=0.003). Even well-validated wrist blood pressure devices can show a clinically relevant bias in patients with elevated pulse pressure. Increased arterial stiffness may impair the accuracy of oscillometric blood pressure measurement at the wrist.