Long-Term Prognostic Value of Blood Pressure Variability in the General Population

TLDR

Blood pressure variability has been proposed to influence cardiovascular prognosis, but existing data are inconsistent and long‑term studies are lacking. In 2012, a random sample of Monza residents underwent 24‑hour ambulatory blood pressure monitoring every 20 minutes, and variability was quantified by SDs of 24‑hour, day, and night values, day‑night diastolic differences, and residual erratic components derived from Fourier analysis, with events tracked for 148 months. After adjusting for age, sex, mean BP, and other risk factors, only residual erratic diastolic variability and nocturnal hypotension attenuation independently predicted mortality, with erratic variability being the strongest predictor, while mean BP SDs showed no association and day‑night diastolic difference was inversely related to cardiovascular death risk.

Abstract

The hypothesis has been advanced that cardiovascular prognosis is related not only to 24-hour mean blood pressure but also to blood pressure variability. Data, however, are inconsistent, and no long-term prognostic study is available. In 2012 individuals randomly selected from the population of Monza (Milan), 24-hour ambulatory blood pressure (Spacelabs 90207) was measured via readings spaced by 20 minutes. Systolic and diastolic blood pressure variability was obtained by calculating the following: (1) the SD of 24-hour, day, and night mean values; (2) the day-night blood pressure difference; and (3) the residual or erratic blood pressure variability (Fourier spectral analysis). Fatal cardiovascular and noncardiovascular events were registered for 148 months. When adjusted for age, sex, 24-hour mean blood pressure, and other risk factors, there was no relationship between the risk of death and 24-hour, day, and night blood pressure SDs. In contrast, the adjusted risk of cardiovascular death was inversely related to day-night diastolic BP difference (beta coefficient=-0.040; P<0.02) and showed a significant positive relationship with residual diastolic blood pressure variability (beta coefficient=0.175; P<0.002). Twenty-four-hour mean blood pressure attenuation of nocturnal hypotension and erratic diastolic blood pressure variability all independently predicted the mortality risk, with the erratic variability being the most important factor. Our data show that the relationship of blood pressure to prognosis is complex and that phenomena other than 24-hour mean values are involved. They also provide the first evidence that short-term erratic components of blood pressure variability play a prognostic role, with their increase being accompanied by an increased cardiovascular risk.