Isolated Systolic Hypertension and Isolated Diastolic Hypertension Identified With Ambulatory Blood Pressure: Longitudinal Association With Cardiovascular Events in the Young

Objective: The clinical relevance and adverse consequences of isolated diastolic hypertension (IDH) and isolated systolic hypertension (ISH) in young people have been questioned. Most results were obtained with office blood pressure (BP) while only a few data were based on out-of-office BP. The aim of the present study was to investigate the predictive value for major adverse cardiovascular events (MACE) of IDH and ISH of the young identified with 24-hour ambulatory BP. Design and method: We investigated 1201 subjects with mean age 33.1±8.5 years, 72.8% males. Using the 130/80 mmHg 24-hour BP cut-off, 269 participants had normal BP, 277 had IDH, 206 had ISH, and 449 had systolic-diastolic hypertension (SDH). The risk of MACE in the four groups was calculated using multivariate Cox regressions. Results: Office IDH and ISH were poorly correlated with ambulatory IDH and ISH (R=0.35 and 0.32, respectively). During 19 years of follow-up, there were a total of 136 MACE. In multivariate Cox regression adjusted for age, gender, parental cardiovascular disease, smoking, alcohol, coffee use, physical activity, body mass index, serum glucose, total cholesterol, and HDL-cholesterol, the lowest hazard ratio (HR) of MACE was found in the IDH participants who were taken as the reference group. Compared to IDH, the HR was 2.8 (95%CI,1.5-5.2, p=0.001) in ISH and 2.1 (1.3-3.4, p=0.003) in SDH. No significant difference was found between IDH and the normal ambulatory BP group. Inclusion of office BP and antihypertensive treatment during follow-up in the model only marginally affected the difference between the groups. Using ambulatory BP as a continuous variable, pulse pressure (p=0.011) but not mean BP (p=0.59) was a significant predictor of outcome. No group defined according to office BP was independently associated with MACE. Conclusions: These data indicate that in young subjects, IDH identified according to ambulatory BP is at lower risk of MACE compared to ISH and SDH. Patients with ambulatory ISH are at high risk of cardiovascular disease to the same extent as those with SDH and should be given antihypertensive treatment. Pulse pressure assessed with ambulatory monitoring has important prognostic value also in young individuals.