Association of blood pressure measurements in sitting, supine, and standing positions with the 10-year risk of mortality in Korean adults

OBJECTIVES: This prospective cohort study investigated the association between blood pressure (BP) as measured in different body postures and all-cause and cardiovascular (CV) mortality risk. METHODS: This population-based investigation included 8,901 Korean adults in 2001 and 2002. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured sequentially in the sitting, supine, and standing positions and classified into 4 categories: (1) normal, SBP <120 mmHg and DBP <80 mmHg; (2) high normal/prehypertension, SBP 120-129 mmHg and DBP <80 mmHg/SBP 130-139 mmHg or DBP 80-89 mmHg; (3) grade 1 hypertension (HTN), with SBP 140-159 mmHg or DBP 90-99 mmHg; and (4) grade 2 HTN, SBP ≥160 mmHg or DBP ≥100 mmHg. The date and cause of individual deaths were confirmed in the death record data compiled until 2013. Data were analyzed using Cox proportional hazard regression. RESULTS: Significant associations were found between the BP categories and all-cause mortality, but only when BPs were measured in the supine position. The multivariate hazard ratios (95% confidence intervals, [CIs]) were 1.36 (95% CI, 1.06 to 1.75) and 1.59 (95% CI, 1.06 to 2.39) for grade 1 HTN and grade 2 HTN, respectively, compared with the normal category. The associations between the BP categories and CV mortality were significant regardless of body posture among participants ≥65 years, whereas they were significant for supine BP measurements only in those <65 years. CONCLUSIONS: BP measured in the supine position predicted all-cause mortality and CV mortality better than BP measured in other postures.