CHICAGO, May 21 -- Obesity appears to be associated with an increased risk of diastolic rather than systolic hypertension subtypes, researchers said here.
Although most doctors focus on isolated systolic hypertension in treating patients with high blood pressure, diastolic subtypes tend to predominate in obese patients and require scrutiny and therapy, said Julio Chirinos, M.D., of the University of Miami.
"Large artery stiffness is associated with isolated hypertension," he said at the American Society of Hypertension meeting, "but our findings suggest that other hemodynamic determinants contribute to the public burden of obesity-related hypertension in the U.S."
In his presentation, Dr. Chirinos reported that among patients with a body mass index greater than 35 -- or the morbidly obese -- fewer than half with high blood pressure have isolated systolic hypertension.
According to data from the Third National Health and Nutrition Examination Survey (NHANES III) conducted by the National Institutes of Health from 1988 to 1994, 23.5% of the morbidly obese patients were diagnosed with systodiastolic hypertension and 32.7% were diagnosed with isolated diastolic blood pressure. That left 43.9% with isolated systolic blood pressure.
Dr. Chirinos also noted, "Younger people with hypertension are more likely to be obese compared to older adults with hypertension. Obese hypertensives are more likely to exhibit subtypes of hypertension than their leaner counterparts."
The association between obesity and the diastolic subtypes also included those patients with a BMI that is considered obese: 30 to 30.9. About 51.2% of these patients had isolated systolic blood pressure, while 48.8% had the diastolic subtype diagnosis. Among overweight patients with high blood pressure, nearly 60% had isolated systolic hypertension.
Among normal-weight hypertensives, 71% had isolated systolic hypertension and among thin patients with high blood pressure, isolated systolic hypertension accounted for 77.5% of the group, Dr. Chirinos reported.
He said that the analysis of nearly 17,000 people with high blood pressure indicates that for every two-point unit increase in BMI there was an associated 5.8% (95% CI=4.7-7.0%) increased risk of systolic hypertension and a 10.1% (95% CI=8.9-11.3%) increase in the risk of diastolic hypertension. Those increases were statistically significant at the P