Optimal Blood Pressure in Elderly Hypertensive Subjects: A Korean National Health Insurance Service Health Examinee Cohort Study

Background: To describe the association between mean blood pressure (BP) and clinical outcomes and to investigate the optimal BP in elderly hypertensive subjects. Methods: This study used the National Health Insurance Service health examinee cohort. Subjects aged >60 years with a new diagnosis of hypertension from 2003 to 2006 were selected. Patients with previous major cardiovascular events were excluded. The remaining 23,523 subjects were divided into three groups according to the average of the observed systolic BP (SBP) and diastolic BP (DBP): (i) average SBP <130 mm Hg (n = 6,893), 130-140 mm Hg (n = 8,676), and ≥140 mm Hg (n = 7,954) or (ii) average DBP <80 mm Hg (n = 9,273), 80-90 mm Hg (n = 11,607), and ≥90 mm Hg (n = 2,643). Results: Compared with SBP ≥140 mm Hg, SBP 130-140 mm Hg was associated with significantly lower rates of all-cause mortality (hazard ratio (HR) = 0.69, 95% confidence interval (CI) = 0.62-0.76, P < 0.001) and cardiovascular mortality (HR = 0.61, 95% CI = 0.50-0.75, P < 0.001). However, SBP <130 mm Hg did not show further lowering of all-cause and cardiovascular mortality rates compared with SBP 130-140 mm Hg. DBP 80-90 mm Hg was also associated with lower risks of all-cause death (HR = 0.64, 95% CI = 0.57-0.72, P < 0.001) and cardiovascular death (HR = 0.51, 95% CI = 0.40-0.64, P < 0.001) compared with DBP ≥90 mm Hg. There were no additional benefits with DBP <80 mm Hg for all-cause death and cardiovascular death. Conclusions: Mean BP of <140/90 mm Hg were associated with lowest all-cause and cardiovascular mortality without any further benefit with mean BP <130/80 mm Hg.