Three simple steps for improving diagnostic accuracy in hypertension

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenObjective: Most patients have only had three measurements of blood pressure before being labelled as hypertensive. This abbreviated assessment may lead to inaccurate classification, unnecessary treatment and dilution in treatment benefit for the population. We aimed to explore how accurate current methods are in diagnosing mild hypertension, and to explore practical methods of improving targeting of antihypertensive treatment using clinic visits but without lengthy observation. Material and methods: We applied current diagnostic methods to 3965 individuals with mild hypertension who were followed for a year in the placebo arm of the MRC Mild Hypertension Trial (Medical Research Council). We thus calculated the proportion selected for treatment by current methods and the diagnostic accuracy, using average blood pressure beyond six months as representing "true" long-term blood pressure. We looked at the benefit of averaging blood pressures, prolonging observation modestly and estimating within-person blood pressure variability. Results: Prolonging observation to three months selects a smaller (by about 12%) proportion of the sample for treatment. At three months the proportion of the sample selected is similar to the proportion defined as "truly" hypertensive. The diagnostic accuracy of current methods is poor with up to 69% discrepancy in classification. This discrepancy was improved in absolute terms by up to 18% by prolonging observation to three months and using average blood pressures. Identifying those individuals with low within-person variability allows marked improvement in the prediction of "true" hypertension. Conclusion: Although some inaccuracy in the diagnosis of hypertension is inevitable, observation for three months, averaging blood pressures and estimating within-person blood pressure variability can markedly improve upon current methods used for targeting antihypertensive treatment.Tilgangur: Flestir sem greindir hafa verið með háþrýsting hafa fengið greininguna eftir þrjár eða færri mælingar á blóðþrýstingi hjá lækni. Þetta skyndimat gæti leitt til ónákvæmni í greiningu, ónauðsynlegrar meðhöndlunar og minni meðferðarávinnings en efni standa til. Við höfum reynt að meta hversu nákvæm greining fæst með hefðbundnum aðferðum og skoðað hagnýt ráð sem beita mætti til þess að bæta öryggi greiningarinnar án þess að seinka greiningu um of. Efniviður og aðferðir: 3965 manns var fylgt eftir í lyfleysuhluta "MRC Mild Hypertension Trial" (Medical Research Council). Hlutfall hópsins sem myndi hafa valist til meðferðar samkvæmt algengum klínískum vinnubrögðum var metið og einnig var reynt að áætla nákvæmni þeirrar greiningar með samanburði við meðalþrýsting eftir meira en sex mánaða eftirfylgni sem var talið ígildi raunverulegs langtímablóðþrýstings. Við litum á kosti þess að nota meðalþrýsting nokkurra heimsókna, eftirlit og bið í tiltölulega skamman tíma (þrjá mánuði) og áhrif þess að taka tillit til breytileika blóðþrýstings hvers einstaklings. Niðurstöður: Greining háþrýstings eftir þriggja mánaða eftirlit fremur en eftir þrjár mælingar minnkar hópinn sem talinn er hafa háþrýsting um næstum 12%. Ekki virtist ávinningur af því að lengja eftirlitið frekar. Greining háþrýstings samkvæmt þeim hefðbundnu vinnubrögðum sem oftast er beitt núna er ónákvæm og leiðir hugsanlega til rangrar greiningar hjá allt að 69% einstaklinga. Ónákvæmnina má minnka um allt að 18% með því að bíða með greiningu í þrjá mánuði og með því að nota meðalblóðþrýsting nokkurra heimsókna. Auðveldara reynist að spá fyrir um raunverulegan langtímablóðþrýsting með því að leggja mat á breytileika blóðþrýstings. Ályktun: Nokkur ónákvæmni í greiningu háþrýstings er óhjákvæmileg en auka má verulega öryggi greiningarinnar með því að fylgja fólki eftir í þrjá mánuði, nota meðalblóðþrýsting og leggja mat á breytileika blóðþrýstings hvers og eins

Computerized reporting improves the clinical use of ambulatory blood pressure measurement

a Background Ambulatory blood pressure measurement (ABPM) is being used increasingly in clinical practice. One previous study has shown that there can be considerable variance between expert observers in the interpretation of ABPM data. The purpose of this study was to show whether computer-generated reports with the dabl s ABPM system would provide more consistency in the interpretation of data than reports from expert observers. Methods Twenty-six international experts in hypertension were invited to participate and 17 agreed to do so. Twelve ABPMs generated by the Spacelabs device that were considered representative of the patterns likely to be seen in practice were sent to each participant for reporting. The corresponding dabl reports with an automatic interpretation were generated according to the European Society of Hypertension guideline for comparison with the observer reports. Each of the observer-interpreted Spacelabs reports for the 12 ABPM patterns were coded, analysed and compared with the automatically interpreted dabl s ABPM reports. Both sets of data were analysed for interobserver variability, observer v dabl s ABPM consistency and the time taken for observer reportage. The main analysis determined issues of definite disagreement, namely the presence or absence of nocturnal dipping. Further analysis determined the presence or absence of white-coat phenomena and the severity of hypertension. Results Incorrect diagnoses were made in 13 instances. White-coat hypertension and white-coat effect, although obvious in many instances, were not identified in five ABPMs; the severity of hypertension was not reported in four ABPMs; the severity of nocturnal hypertension was not diagnosed in one ABPM by nine experts and isolated diastolic hypertension was not identified by six experts in two ABPMs. Conclusion This study provides evidence to show that observer variance in reporting ABPMs is common even among experts and that computer-generated interpretative reports of ABPM data improve the diagnostic decisions based on the data generated by 24-h blood pressure recording

The case for home monitoring in hypertension

Although the assessment of cardiovascular risk in individual patients takes into account a range of risk factors, the diagnosis and management of hypertension (high blood pressure) is largely determined by a single numerical value, albeit that often several readings are taken over time. Given the critical impact of a decision to embark on lifelong drug therapy, the importance of ensuring that a blood pressure (BP) record is both accurate and representative is clear. However, there is good evidence that the variability of BP is such that even if measurement is of the highest quality, it can be difficult to say with confidence whether a patient is above or below a treatment threshold. This commentary argues that current BP measurement is inadequate to make the clinical decisions that are necessary and that multiple readings are required to deliver an acceptable degree of accuracy for safe decision-making. This is impractical in a doctor's surgery, and the only realistic long-term strategy is to involve the patient in measuring his or her own BP in their own environment. Evidence is presented that such a strategy is better able to predict risk, is cost-effective for diagnosing hypertension, can improve BP control and is thus better able to protect individuals in the future

Sketch-based interaction and modeling: where do we stand?

Sketching is a natural and intuitive communication tool used for expressing concepts or ideas which are difficult to communicate through text or speech alone. Sketching is therefore used for a variety of purposes, from the expression of ideas on two-dimensional (2D) physical media, to object creation, manipulation, or deformation in three-dimensional (3D) immersive environments. This variety in sketching activities brings about a range of technologies which, while having similar scope, namely that of recording and interpreting the sketch gesture to effect some interaction, adopt different interpretation approaches according to the environment in which the sketch is drawn. In fields such as product design, sketches are drawn at various stages of the design process, and therefore, designers would benefit from sketch interpretation technologies which support these differing interactions. However, research typically focuses on one aspect of sketch interpretation and modeling such that literature on available technologies is fragmented and dispersed. In this paper, we bring together the relevant literature describing technologies which can support the product design industry, namely technologies which support the interpretation of sketches drawn on 2D media, sketch-based search interactions, as well as sketch gestures drawn in 3D media. This paper, therefore, gives a holistic view of the algorithmic support that can be provided in the design process. In so doing, we highlight the research gaps and future research directions required to provide full sketch-based interaction support

The impact of supported telemetric monitoring in people with type 2 diabetes: study protocol for a randomised controlled trial

BackgroundDiabetes prevalence is increasing and current methods of management are unsustainable. Effective approaches to supporting self-management are required. The aim of this randomized controlled trial is to establish whether supported telemetric monitoring of glycemic control and blood pressure results in reductions in glycosylated hemoglobin (HbA1c; the primary outcome of a measure of long-term glycemic control) and secondary outcomes of blood pressure and weight among people with poorly controlled diabetes compared to a control group receiving usual care.Methods/DesignDesign: multi-center, randomized controlled trial with embedded qualitative study.Setting: primary care in Lothian, Kent, Glasgow and Borders regions in the UK.Participants: people with type 2 diabetes and confirmed HbA1c >7.5% (58 mmol/mol).Intervention/comparison: randomization to intervention or control groups will be performed by the Edinburgh Clinical Trials Unit. Participants in the intervention group will be shown how to use blood glucose and blood pressure monitors and weighing scales which use Bluetooth wireless technology to transmit readings via modem to a remote server. These participants will be asked to provide at least twice weekly measurements of morning and evening blood glucose and weekly measurements of weight and blood pressure. Measurements will be checked at least weekly by practice nurses who will contact the patients to adjust therapy according to guidelines and reinforce lifestyle advice. Participants in the control group will receive usual care. All participants will receive an individual education session.ollow-up: measurements will be performed at practices 9 months after randomization by research nurses blinded to allocation. The primary outcome measure is HbA1c and secondary outcomes measure are daytime systolic and diastolic blood pressure, weight and cost per quality-adjusted life year.Analysis: intention-to-treat analyses will be performed. The sample size of 320 participants allows for 20% drop-out and has 80% power at 5% significance to detect a 0.5% absolute (6 mmol/mol) fall in HbA1c in the intervention group. The qualitative study will explore the experiences of patients and professionals using the intervention

Examining the effectiveness of telemonitoring with routinely acquired blood pressure data in primary care: challenges in the statistical analysis

BackgroundScale-up BP was a quasi-experimental implementation study, following a successful randomised controlled trial of the roll-out of telemonitoring in primary care across Lothian, Scotland. Our primary objective was to assess the effect of telemonitoring on blood pressure (BP) control using routinely collected data. Telemonitored systolic and diastolic BP were compared with surgery BP measurements from patients not using telemonitoring (comparator patients). The statistical analysis and interpretation of findings was challenging due to the broad range of biases potentially influencing the results, including differences in the frequency of readings, ‘white coat effect’, end digit preference, and missing data.MethodsFour different statistical methods were employed in order to minimise the impact of these biases on the comparison between telemonitoring and comparator groups. These methods were “standardisation with stratification”, “standardisation with matching”, “regression adjustment for propensity score” and “random coefficient modelling”. The first three methods standardised the groups so that all participants provided exactly two measurements at baseline and 6–12 months follow-up prior to analysis. The fourth analysis used linear mixed modelling based on all available data.ResultsThe standardisation with stratification analysis showed a significantly lower systolic BP in telemonitoring patients at 6–12 months follow-up (-4.06, 95% CI -6.30 to -1.82, p

Peat swamp forest conservation withstands pervasive land conversion to oil palm plantation in North Selangor, Malaysia

Tropical deforestation remains one of the major global challenges of the twenty-first century driven to a large extent by the conversion of land for agricultural purposes, such as palm oil production. Malaysia is one of the world’s largest palm oil producers and has seen widespread conversion to oil palm from primary forest, including peat swamp forest (PSF). This study investigates the rate and extent of pervasive oil palm expansion in and around North Selangor Peat Swamp Forest (NSPSF) over the last three decades, exploring how land conversion has affected the region’s tropical forests, and assessing the relative success of PSF conservation measures. Time-series Landsat imagery was used to assess thematic land cover change and improvement in vegetation condition since NSPSF was given protected status in 1990. The results show a near tripling in oil palm cover throughout North Selangor, from 24,930 ha in 1989 to 70,070 ha in 2016; while at the same time tropical forest cover shrank from 145,570 ha to 88,400 ha. Despite concerns over the sustainability and environmental impact of such rapid oil palm conversion at a regional level, at the local scale, NSPSF represents a relative conservation success story. Effective land stewardship by government and non-governmental organization (NGO) management actors has limited illegal encroachment of oil palm around the reserve boundary. PSF rehabilitation measures have also markedly improved vegetation condition in NSPFS’s interior. These findings have broad significance for how oil palm agriculture is managed and especially for PSF stewardship and conservation, and the approaches described here may be usefully adopted elsewhere in Southeast Asia and around the world

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, bu