Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.726441
Title: The utility of out of office blood pressure measurement
Author: McGowan, Neil
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2010
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Abstract:
Ambulatory blood pressure measurement (ABPM) has improved prognostic power with respect to cardiovascular disease compared with office blood pressure (BP). It can be postulated that this is secondary to improved reproducibility of measurement, as a result of ABPMs ability to remove most of the factors leading to within-subject variability of BP measurement. In addition, the number of BP readings obtained from ABPM results in a statistically more accurate reflection of mean BP compared with a single office BP measurement. Repeated episodes of ABPM, with time intervals of six months to greater than three years, were examined in a cohort of treatment naïve subjects. BP was more reproducible when expressed as a continuous variable, as defined by the intra-class correlation coefficient (ICC), than when BP was referred to as a dichotomous variable (hypertensive/normotensive), as defined with a kappa statistic. This was true independent of time interval between episodes of monitoring. Linear regression analysis or multivariate binomial regression indicated that nocturnal blood pressure dip, expressed as either a continuous or dichotomous variable, was unable to be predicted from age, sex, mean awake systolic BP. Nocturnal blood pressure dipping was poorly reproducible when expressed as a dichotomous variable (dipper/non-dipper), irrespective of the time interval between measurements (k=0.29). Intra class correlation coefficient demonstrated improved reproducibility of nocturnal pressure fall when this is expressed as a percentage reduction of mean awake BP (ICC=0.6). This was constant independent of time interval. ABPM was used to demonstrate a significant BP reduction in patients with diabetes and high vascular risk, managed through a pharmacist-led cardiovascular risk clinic. Repeat ABPM six months post discharge was not significantly different from BP on discharge from the clinic. ABPM data currently needs clinician interpretation. Four studies, using national and international experts in hypertension, indicated poor agreement in interpretation and diagnosis of hypertension when all were faced with identical ABPM data. Computer software can be used to standardise diagnosis but management decisions will always rest with clinicians. Self blood pressure monitoring has been proposed as the future of hypertension management. Mean BP obtained with self monitoring of BP (SBPM), using the schedule defined by the European Society of Hypertension, was not significantly different to mean awake-time BP on ABPM. In addition, SBPM was preferred by over 80% of subjects. The author suggests that using only office BP for measuring blood pressure is outdated and inaccurate. The aim of this thesis was to demonstrate the utility of out of office blood pressure measurement and recommends this becomes part of everyday clinical practice. It is time hypertension management was brought into the 21st century!
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.726441  DOI: Not available
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