Day-to-Day Home Blood Pressure Variability and Orthostatic Hypotension: The Nagahama Study

BACKGROUND The aim of this study is to clarify associations between orthostatic blood pressure (BP) change, as well as possible physiological factors, and day-to-day home BP variability, a promising risk factor for cardiovascular outcomes. METHODS Study participants were 6,465 community residents (age 58.3 years). Home BP was measured every morning and evening for 7 days. Orthostatic BP was calculated as the maximum difference between BP measured while sitting and remeasured after 1 and 3 minutes standing. RESULTS Frequency of individuals who showed orthostatic BP decline was as follows: systolic BP (SBP) change ≥−20 mm Hg: 2.6%, ≥−10 mm Hg: 14.1%. These subgroups showed larger home SBP variability (average real variability: 11.3 ± 5.3, 8.7 ± 3.9 mm Hg) when compared with orthostatic normotensives (7.6 ± 3.7 mm Hg) (all P < 0.001). Multiple linear regression analysis adjusted for major covariates, including seated BP, identified orthostatic BP drop as an independent determinant for morning BP variability (≥−20 mm Hg: β = 0.037, P = 0.003; ≥−10 mm Hg: β = 0.026, P = 0.036) but not for evening BP variability. Carotid hypertrophy was significantly associated with home BP variability (morning: β = 0.052, P = 0.001; evening: β = 0.065, P < 0.001) and showed a U-shaped association with orthostatic BP change. Plasma B-type natriuretic peptide level, a previously suggested factor for BP variability, did not show significant association with morning and evening BP variability. CONCLUSION Orthostatic BP decline was significantly associated with morning BP variability. Large artery atherosclerosis was a common risk factor.