Low Systolic Blood Pressure and Vascular Mortality Among More Than 1 Million Korean Adults

Abstract

Blood pressure (BP) has been reported to be directly related to mortality from vascular disease down to at least 115/75 mm Hg with no clear threshold level.1 Evidence from previous research suggests that low BP is a predictor of mortality in various clinical settings, and J-or U-curve associations between BP and vascular mortality have been reported among the elderly and those with vascular or other diseases.2-9 Low BP, even a single incidence of isolated hypotensive BP in certain situations, can predict mortality, 10 but despite the evidence, physicians often ignore low BP. 10,11 There is no doubt, however, that a J-curve association between BP and mortality exists, even in the general population with no known comorbid diseases, because adequate perfusion to vital organs is difficult to sustain below a certain BP. In nonclinical populations, a few studies have found that low BP was associated with a higher mortality from vascular disease.12-14 However, it is unclear whether and in what range of BP a J-curve occurs. We conducted a large prospective cohort study with >1 million participants to demonstrate whether a J-curve association exists between systolic BP (SBP) and mortality from vascular disease in a nonclinical population. We focused on SBP, because SBP has been shown to be a better predictor of mortality from vascular disease than diastolic BP (DBP) or pulse pressure in prospective studies among the general population. 1,15,16 Clinical Perspective on p 2390 Methods Study ParticipantsThe Korean Cancer Prevention Study comprises 1 329 525 individuals (482 618 women) aged 30 to 95 years who underwent at least 1 routine medical examination by the Korean Medical Insurance CorporationBackground-The association between low systolic blood pressure (SBP) and vascular disease is unclear, especially in nonclinical populations. Methods and Results-We studied 1 235 246 individuals who participated in routine medical examinations between 1992 and 1995. The hazard ratios (HRs) were adjusted for potential confounders. During 22.7 million person-years of follow-up, 34 816 individuals died of atherosclerotic vascular diseases. An increase in SBP was directly related to an increase in vascular mortality at SBP above ≈100 mmHg. The group with the lowest SBP (<90 mm Hg) had a higher HR for mortality from atherosclerotic vascular disease (HR, 1.53; 95% confidence interval, 1.15-2.03) in comparison with those with an SBP of 90 to 99 mm Hg. The HR associated with the lowest SBP was 2.54 (95% confidence interval, 1.51-4.29) for ischemic heart disease and 1.21 (95% confidence interval, 0.79-1.85) for stroke. Regarding stroke subtype, mortality from hemorrhagic stroke (HR per 10 mm Hg increase, 0.53; 95% confidence interval, 0.29-0.96), rather than mortality from ischemic stroke (HR per 10 mm Hg increase, 1.00; 95% confidence interval, 0.51-1.97), was inversely associated with SBP when SBP fell to <100 mm Hg. Even when excluding the first 5 years of follow-up, the HRs associated with the lowest SBP did not decrease. The invers...

Age-specific associations between systolic blood pressure and cardiovascular mortality

“…Rapsomaniki et al reported non-significant risk elevation for each CVD subtype, including MI, except for stable angina, in the BP range of 115–140 mm Hg among the elderly 9. Yi et al previously reported that the nadir risk was near an SBP of 100 mm Hg, with increasing risk for higher BPs 4. However, that study defined the elderly population broadly (60–95 years), thereby including many individuals aged 60–69 years.…”

Longitudinal change in blood pressure is associated with cardiovascular disease mortality in a Chinese cohort

“…A study of 1 235 246 individuals from the Korean Cancer Prevention Study has indicated J-curve associations between SBP and vascular mortality 16. The Systolic Blood Pressure Intervention Trial17 Research Group concluded that among patients at high risk for cardiovascular events but without diabetes mellitus, lowering SBP to a target goal of less than 120 mm Hg rather than <140 mm Hg could reduce 25% risk of major cardiovascular events and 43% of cardiovascular mortality.…”

Baseline and longitudinal change in blood pressure and mortality in a Chinese cohort

“…A prospective study including over 1 million Korean adults has suggested that subjects with the lowest systolic BP had higher HRs for mortality from ischaemic heart disease, stroke and atherosclerotic vascular disease 30. Data from the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial  (ONTARGET) and Telmisartan Randomized AssessmeNt Study in ACE iNtolerant participants with cardiovascular Disease (TRANSCEND) trials suggested that compared with a DBP of 70–<80 mm Hg, lower DBP was associated with a higher risk of all-cause and CVD mortality in patients achieving an SBP of 120–<140 mm Hg 32.…”