Both daytime and night-time blood pressure are vital prognostic indicators, with the value of each dependent on the outcome being measured. As a result, blood pressure should be recorded during the whole day. These are the conclusions of authors of an Article published in this week’s edition of The Lancet.
Professor Jan Staessen, Department of Cardiovascular Diseases, University of Leuven, Belgium and colleagues studied 7458 people across six countries in Asia, South America and Europe, with an average age of 56.8 years, and followed them up for an average of just under 10 years.
They found that, in contrast to commonly held views, daytime blood pressure adjusted for night-time blood pressure predicts fatal combined with non-fatal cardiovascular events, except in treated patients - in whom antihypertensive drugs might reduce blood pressure during the day, but not at night, and mask the relationship between outcome and the daytime blood pressure. The increased mortality in patients with higher night-time than daytime blood pressure probably indicates reverse causality. They also found that participants with systolic night-to-day ratio values of one or more were older, at higher risk of death, and died at an older age than those whose night-to-day ratio was normal (between 0.8 and 0.9).
The authors conclude: “Our findings have implications for clinical practice and research. The night-time blood pressure predicted mortality and non-fatal outcomes, irrespective of treatment status. The daytime blood pressure independently predicted the composite of all fatal and non-fatal cardiovascular events, especially in untreated participants. Our findings therefore support recording the ambulatory blood pressure during the whole day.”
In an accompanying Comment, Professor Stéphane Laurent, Hôpital Europeén Georges Pompidou, and Université Paris-Descartes, Paris, France, says: “Although the findings of Staessen and colleagues are in favour of recording the ambulatory blood pressure for the whole day, the question arises as to whether 24-h blood pressure values from patients taking antihypertensive therapy should be interpreted differently from those of untreated participants. The results of their study might thus have important clinical implications and significantly affect the next guidelines for ambulatory blood pressure measurement.”
The paper can be viewed at the link below
http://multimedia.thelancet.com/pdf/press/Bpressure.pdf
Journal
The Lancet