The applicability of home blood pressure measurement in clinical practice: A review of literature

Willem J Verberk, Abraham A Kroon, Heidi A Jongen-Vancraybex, Peter W de LeeuwUniversity Hospital Maastricht, Department of Internal Medicine and Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, The NetherlandsPurpose: To review the literature on home blood pressure measurement (HBPM), to examine its validity and applicability for clinical practice and to provide recommendations regarding HBPM assessment.Findings: HBPM can eliminate the white coat effect and offers the possibility to obtain multiple measurements under standardized conditions, which increases knowledge of overall blood pressure value. Although it is not entirely capable of replacing ambulatory blood pressure measurement (ABPM), HBPM correlates better with target organ damage and cardiovascular mortality than office blood pressure measurement (OBPM), it enables prediction of sustained hypertension in patients with borderline hypertension, and proves to be an appropriate tool for assessing drug efficacy. Additional advantages of HBPM are that it may increase drug compliance and patient’s awareness of hypertension. Overall, OBPM yield higher blood pressure values than HBPM. Differences between OBPM and HBPM tend to increase with age and are generally higher in patients without antihypertensive treatment than in patients with antihypertensive treatment.Recommendations: Measurements should be performed according to accepted guidelines and recordings should be performed with a memory equipped automatic validated device. From the data reviewed here, we recommend that HBPM be assessed monthly by taking two measurements in the morning within 1 hour after awakening and two in the evening for three consecutive days, the data from the first day should be dismissed. A subject should be labeled hypertensive if his/her HBPM value is equal to or greater than 137 mmHg systolic and/or 84 mmHg diastolic.Keywords: blood pressure, hypertension, self-measurement, home measurement, ambulatory measurement, adherenc

Foundation species enhance food web complexity through non-trophic facilitation

Food webs are an integral part of every ecosystem on the planet, yet understanding the mechanisms shaping these complex networks remains a major challenge. Recently, several studies suggested that non-trophic species interactions such as habitat modification and mutualisms can be important determinants of food web structure. However, it remains unclear whether these findings generalize across ecosystems, and whether non-trophic interactions affect food webs randomly, or affect specific trophic levels or functional groups. Here, we combine analyses of 58 food webs from seven terrestrial, freshwater and coastal systems to test (1) the general hypothesis that non-trophic facilitation by habitat-forming foundation species enhances food web complexity, and (2) whether these enhancements have either random or targeted effects on particular trophic levels, functional groups, and linkages throughout the food web. Our empirical results demonstrate that foundation species consistently enhance food web complexity in all seven ecosystems. Further analyses reveal that 15 out of 19 food web properties can be well-approximated by assuming that foundation species randomly facilitate species throughout the trophic network. However, basal species are less strongly, and carnivores are more strongly facilitated in foundation species’ food webs than predicted based on random facilitation, resulting in a higher mean trophic level and a longer average chain length. Overall, we conclude that foundation species strongly enhance food web complexity through non-trophic facilitation of species across the entire trophic network. We therefore suggest that the structure and stability of food webs often depends critically on non-trophic facilitation by foundation species.</p

Individual patient data meta-analysis of self-monitoring of blood pressure (BP-SMART): a protocol.

INTRODUCTION: Self-monitoring of blood pressure is effective in reducing blood pressure in hypertension. However previous meta-analyses have shown a considerable amount of heterogeneity between studies, only part of which can be accounted for by meta-regression. This may be due to differences in design, recruited populations, intervention components or results among patient subgroups. To further investigate these differences, an individual patient data (IPD) meta-analysis of self-monitoring of blood pressure will be performed. METHODS AND ANALYSIS: We will identify randomised trials that have compared patients with hypertension who are self-monitoring blood pressure with those who are not and invite trialists to provide IPD including clinic and/or ambulatory systolic and diastolic blood pressure at baseline and all follow-up points where both intervention and control groups were measured. Other data requested will include measurement methodology, length of follow-up, cointerventions, baseline demographic (age, gender) and psychosocial factors (deprivation, quality of life), setting, intensity of self-monitoring, self-monitored blood pressure, comorbidities, lifestyle factors (weight, smoking) and presence or not of antihypertensive treatment. Data on all available patients will be included in order to take an intention-to-treat approach. A two-stage procedure for IPD meta-analysis, stratified by trial and taking into account age, sex, diabetes and baseline systolic BP will be used. Exploratory subgroup analyses will further investigate non-linear relationships between the prespecified variables. Sensitivity analyses will assess the impact of trials which have and have not provided IPD. ETHICS AND DISSEMINATION: This study does not include identifiable data. Results will be disseminated in a peer-reviewed publication and by international conference presentations. CONCLUSIONS: IPD analysis should help the understanding of which self-monitoring interventions for which patient groups are most effective in the control of blood pressure

Simultaneous double arm automated blood pressure measurement for the screening of subjects with potential vascular disease:a community study

Purpose: Hypertension guidelines recommend measuring blood pressure (BP) on both arms, since an abnormal inter-arm difference (IAD) in BP is associated with an increased risk of vascular abnormalities and cardiovascular (CV) disease. We tested whether an automatic oscillometric BP monitor allowing simultaneous both arm BP measurement might be effective for screening of subjects with potential vascular disease. Materials and methods: 220 consecutive subjects from an unselected sample of individuals of a small Italian community were screened using an automated upper-arm electronic BP monitor (Microlife WatchBP Office). Seated BP was measured in triplicate at 1 min interval. Demographic and clinical data were collected prior to any BP measurement. An average IAD difference >20 mmHg for systolic (S) and/or >10 mmHg for diastolic (D) BP was considered abnormal. Results: In 9 subjects (4.1%) an abnormal IAD was found, with lower BPs measured in the non-dominant arm (147 +/- 28/78 +/- 9 vs. 154 +/- 15/92 +/- 11 mmHg dominant,

Opportunistic screening of atrial fibrillation by automatic blood pressure measurement in the community

OBJECTIVE: Timely detection of atrial fibrillation (AF) may effectively prevent cardiovascular consequences. However, traditional diagnostic tools are either poorly reliable (pulse palpation) or not readily accessible (ECG) in general practice. We tested whether an automatic oscillometric blood pressure (BP) monitor embedded with an algorithm for AF detection might be effective for opportunistic screening of asymptomatic AF in the community. SETTING: A community-based screening campaign in an unselected population to verify the feasibility of AF screening with a Microlife WatchBP Office BP monitor with a patented AFIB algorithm. When possible AF was detected (≥2 of 3 BP measurements reporting AF), a doctor immediately performed a single-lead ECG in order to confirm or exclude the presence of the arrhythmia. The main demographic and clinical data were also collected. PARTICIPANTS: 220 consecutive participants from an unselected sample of individuals in a small Italian community. PRIMARY AND SECONDARY OUTCOME MEASURES: Number of patients detected with AF and diagnosed risk factors for AF. RESULTS: In 12 of 220 participants, the device detected possible AF during the BP measurement: in 4 of them (1.8%), the arrhythmia was confirmed by the ECG. Patients with AF were more likely to be older (77.0±1.2 vs 57.2±15.2 years, p=0.010), obese (50.0 vs 14.4%, p=0.048) and to suffer from a cardiovascular disease (50.0 vs 10.6%, p=0.014) than patients without AF. Participants with a positive BP AF reading and non-AF arrhythmias (n=8) did not differ in their general characteristics from participants with a negative BP AF reading and were younger than patients with AF (mean age 56.4±14.8, p=0.027; 5 of 8 participants aged <65 years). CONCLUSIONS: Opportunistic screening of AF by BP measurement is feasible to diagnose this arrhythmia in unaware participants, particularly in those older than 65 years, who are the target patient group recommended by current AF screening guidelines

Accuracy of oscillometric blood pressure monitors for the detection of atrial fibrillation: a systematic review

Atrial fibrillation (AF) is a significant risk factor for stroke and early detection of AF may help to identify patients in need of treatment. Automated blood pressure (BP) monitors with implemented AF or arrhythmia detection systems may be a useful tool for early diagnosis of AF. A systematic review (Medline/PubMed, Embase, Cochrane) of studies was performed to assess the accuracy of modified BP monitors (for diagnosing AF). A total of five studies (four tests in the physician's office and one at home) were selected. For the most accurate AF detection, three sequential BP measurements should be performed. Direct comparison against a 12-lead ECG showed that the highest sensitivity, 97% (95% CI: 94-100%), for detecting AF was obtained when three readings were assessed with two or three AF-positive readings. The highest specificity (97%) was obtained when performing three measurements, of which all three must be AF positive. The modified BP monitor (Microlife Corporation, Taipei, Taiwan) has high potential in improving AF screening