HDCN Article Review/Hyperlink

Tsuji I, Imai Y, Nagai K, Ohkubo T, Watanabe N, Minami N et al.

Proposal of reference values for home blood pressure measurement: Prognostic criteria based on a prospective observation of the general population in Oshsama, Japan

Am J Hypertens (May) 10:409-418 1997

This study reports a longitudinal observation of 1,913 patients (all subjects over 40 years) in a rural Japanese town. These subjects were instructed in home BP measurement (Omron, HEM 401C) and each took one reading daily for four weeks. Clinical BP was measured with an auscultatory device. The authors then obtained subsequent mortality data. They then examined the association of baseline BP and subsequent mortality. Life table analysis and Cox proportional hazards regression were used.

From the survival data, the authors have proposed reference values for hypertension based on home readings. The mean duration of follow-up was 5 years. Over this period there were 141 deaths (38 due to cerebrovascular disease, 33 due to cancer and 17 due to heart disease). For both systolic and diastolic BP the survival curves were different when the BP was divided into quintiles. The authors found a linear tracking of mortality with home systolic BP. For diastolic BP, there was a U-shaped curve with some excess mortality observed at the lowest quintile. The predictive power of home BP was highly superior to screening BP.

The authors accepted a 10% increased risk of mortality and suggested the following criteria for home BP. For systolic BP hypertension is considered present above 137 mmHg and for diastolic BP above 83 mmHg. Also diastolic BP below 66 mmHg was considered low.

This is the first study to use mortality data to suggest reference values of home BP. The study results however cannot be applied easily because the effects of concomitant cardiovascular risk factors were not considered and there are no follow-up home BP readings other than at baseline. Application of the methodology in other populations will be useful. (George Mansoor, M.D., University of Connecticut)