Friday, October 5, 2007

Combined Daytime And Night Time Blood Pressures Crucial Prognostic Indicators

Combined Daytime And Night Time Blood Pressures Crucial Prognostic Indicators

Med News today

05 Oct 2007

Blood pressure should be monitored throughout the whole 24-hour period, with the value of each daytime and night-time blood pressures dependent on outcome being measured, according to a report in The Lancet, this week's edition.

Professor Jan Staessen, Department of Cardiovascular Diseases, University of Leuven, Belgium and team examined 7,458 individuals in Asia, South America and Europe and followed them up for a period of nearly ten years. Their average age was 56.8 years.

The researchers found that daytime blood pressure adjusted for night-time blood pressure predicts fatal combined with non-fatal cardiovascular events. Patients receiving antihypertensive medications, on the other hand, whose readings may be lower during the day, but not at night, may mask the relationship between outcome and daytime blood pressure. The raised mortality among patients with higher night-time blood pressure than during daytime most likely indicates reverse causality, say the researchers.

The researchers also said that individuals with systolic night-to-day ratio values of one or more tended to be older, at higher risk of death, and died at an older age, compared to people whose night-to-day ratio was normal - between 0.8 and 0.9.

"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," the writers concluded.

"Although the findings of Staessen and colleagues are in favor 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," Professor Stéphane Laurent, Hôpital Europeén Georges Pompidou, and Université Paris-Descartes, Paris, France, wrote in an accompanying Comment.

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