March 9, 2011

Blood Pressure May Be Misclassified In 100 Million Americans

According to researchers, about 100 million Americans may currently be misclassified as having abnormal blood pressure.

Brent Taylor from the Veterans Affairs Health Care System in Minneapolis and the University of Minnesota, along with colleagues, found that these people are not actually more likely to die prematurely than those with "normal" blood pressure.

The researchers found that in those under 50, diastolic blood pressure (DBP) is better at predicting mortality, where as systolic blood pressure (SBD) is a stronger predictor for those over 50.

Taylor and colleagues studied the independent contribution of DBP and SBP on mortality, as well as how these relationships might affect the number of Americans labeled as having abnormal blood pressure.

The researchers examined data for 13,792 people from the National Health and Nutrition Examination Survey for the study.  Taylor and colleagues also looked at data for 6,672 adults from the first National Health Examination Survey, which was carried out between 1959 and 1962.

According to the researchers, people over the age of 50 with SBPs above 140 were significantly more likely to die prematurely than those with normal blood pressure. 

Taylor wrote in the Journal of General Internal Medicine: "Our findings highlight that the choice of approach used to define normal blood pressure will impact literally millions of Americans."

"If we cannot reliably see an effect on mortality in a large group of individuals followed for nearly 20 years, should we define the condition as abnormal? "

"We believe considering this kind of approach represents a critical step in ensuring that diagnoses are given only to those with a meaningful elevation in risk, and targeted towards individuals most likely to benefit," he concluded.


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