The Impact of Systolic and Diastolic Blood Pressure Variability on Mortality Is Modified by Ageing. Data From the Dublin Outcome Study

Objective: 24-hour blood pressure variability (BPV) is independently related to cardiovascular outcomes, but conflicting evidence is available on the relative prognostic importance of systolic and diastolic BPV. Aim of this study was to verify the hypothesis that the association of systolic and diastolic blood pressure variability over 24 hours with cardiovascular mortality in untreated subjects is affected by age. Design and method: 24-hour ambulatory blood pressure monitoring was obtained in 10,500 untreated individuals assessed for hypertension in the frame of the Dublin Outcome Study (age 54.4 ± 14.5 years, 47% males) followed up over a median time of 5.4 years. The association of short-term systolic and diastolic blood pressure variability with cardiovascular deaths (N = 498) was assessed in the entire sample and separately in younger and older age subgroups. Results: Diastolic BPV was directly and independently related to cardiovascular mortality (adjusted hazard ratio (adjHR) for 24-hour weighted standard deviation 1.15 [95% confidence interval 1.07–1.24]) and the strength of this association did not differ significantly among age groups. Conversely, systolic BPV was independently associated with cardiovascular mortality only in younger (<50 years) subjects (adjHR for 24-hour weighted standard deviation 1.68 [95% confidence interval 1.30–2.17]), superseding the predictive value of diastolic BPV in this group (Figure).Conclusions: Diastolic short-term BPV independently predicts cardiovascular mortality in hypertensive subjects at all ages, while systolic BPV seems a particularly strong predictor in young adults. If confirmed, these findings might improve the understanding of the prognostic value of BPV, with new perspectives for its possible clinical application.