| CCS Quebec City 2007 |
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| Written by Administrator | |||||||||||||||
| Friday, 15 May 2009 00:07 | |||||||||||||||
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PREVALENCE OF PREHYPERTENSION IN A LARGE OUTPATIENT AMBULATORY BLOOD PRESSURE MONITORING POPULATION Author Block: A Johri, D Armstrong, D Brouillard, M Matangi Kingston, Ontario Abstract: INTRODUCTION: Optimal blood pressure is defined as <120/80mmHg. Prehypertension using JNC 7 criteria is defined as a systolic blood pressure between 120-139mmHg or a diastolic blood pressure between 80-89mmHg. A high normal range using the JNC 6 definition is a systolic blood pressure between 130-139mmHg or a diastolic blood pressure between 85-89mmHg. Recent evidence from the TROPHY trial has shown a 66% relative risk reduction at 2 years in the development of stage 1 hypertension in this JNC 6 high normal group when treated with candesartan. The purpose of our study was to investigate the prevalence of prehypertension using the high normal JNC 6 definition in a large cohort of patients referred to an outpatient cardiac facility for 24hr Ambulatory Blood Pressure Monitoring (ABPM). METHODS: From June 1999 to April 2007 13,459 ABPM were performed at the Kingston Heat Clinic. All data were entered into a comprehensive database called CARDIOfile for later retrieval and analysis. There were 5,158 ABPM performed on patients who were not being treated with antihypertensive medication. These 5,158 patients were used in the subsequent analysis. For simplicity only systolic BP was considered. We used a modification of the TROPHY trial definition for prehypertension because we used 24hr ABPM average systolic daytime recordings. Abnormal blood pressure measurements using 24hr ABPM are 5mmHg lower than office measurements. Therefore we defined prehypertension as an average daytime 24hr systolic ABPM of 125-134mmHg. Hypertension is defined as an average daytime 24hr systolic ABPM of >134mmHg. RESULTS: See Table 1. CONCLUSIONS: The prevalence of prehypertension in our population was high. Almost 30% of patients presenting to our clinic for 24hr ABPM fulfill the TROPHY trial criteria for the diagnosis of prehypertension. Our data may overestimate the prevalence of prehypertension because this was a selected population referred for assessment of hypertension. Before extrapolating the use of antihypertensive drug therapy to this prehypertensive population, large scale clinical trials using hard endpoints are required, rather than the surrogate endpoint of a reduction in the incidence of stage 1 hypertension.
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