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Systolic, diastolic BP increase risk for CV events regardless of hypertension definition
Systolic and diastolic hypertension independently affected the risk for adverse CV events, including MI, hemorrhagic stroke and ischemic stroke, regardless of whether hypertension was defined as BP of at least 140/90 mm Hg or at least 130/80 mm Hg, according to a study published in The New England Journal of Medicine.
“Doctors and patients should make sure that both systolic blood pressure and diastolic blood pressure get attention when it comes to diagnosing and treating hypertension,” Alexander C. Flint, MD, PhD, neurointensivist and stroke specialist at the Permanente Medical Group in Redwood City, California, told Cardiology Today. “By providing additional support to the two thresholds for hypertension defined in the latest AHA/ACC guidelines (> 140/90 and >130/80), we hope that our results will encourage broader adoption of the guideline recommendations.”
Researchers analyzed data from 1,316,363 patients (median age, 53 years; 57% women) from Kaiser Permanente Northern California who had at least one BP measurement at baseline and at least two measurements during the observation period.
There were 36,784,850 BP measurements taken throughout the study. Of the patients in this study, 533,353 had a mean BP of at least 130/80 mm Hg and 118,159 had a mean BP of at least 140/90 mm Hg.
The composite outcome events of interest included ischemic stroke, hemorrhagic stroke or MI during an observation period of 8 years. Several covariates were assessed, including sex, age, race/ethnicity, coexisting conditions and BMI.
Independent predictors of the composite outcome were a continuous burden of systolic hypertension defined as at least 140 mm Hg (HR per unit increase in z score = 1.18; 95% CI, 1.17-1.18) and diastolic hypertension defined as at least 90 mm Hg (HR per unit increase in z score = 1.06; 95% CI, 1.06-1.07). Results were similar when systolic hypertension was defined as at least 130 mm Hg (HR per unit increase in z score = 1.18; 95% CI, 1.17-1.19) and when diastolic hypertension was defined as at least 80 mm Hg (HR per unit increase in z score = 1.08; 95% CI, 1.06-1.09).
There was a J-curve relationship between diastolic BP and the composite outcome, which may be explained in part by age and other covariates. It may also be explained by a higher effect of systolic hypertension in patients in the lowest quartile of diastolic BP.
“Further research is needed to determine the relative impact of systolic and diastolic blood pressures in the initial diagnosis of hypertension,” Flint said in an interview. “If clinicians don’t fully recognize diastolic hypertension, it can’t be appropriately treated. We are also interested in using advanced statistical methods to explore how variation and trends in outpatient vital signs over time may better predict cardiovascular risk.” – by Darlene Dobkowski
For more information:
Alexander C. Flint, MD, PhD, can be reached at Division of Research and Department of Neuroscience, Kaiser Permanente, 1150 Veterans Blvd., Redwood City, CA 94063; email: alexander.c.flint@kp.org; Twitter: @neuroicudoc.
Disclosures: The study was funded by the Kaiser Permanente Northern California Community Benefit Program. Flint reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.