Association Between Annual Visit-to-Visit Blood Pressure Variability and Stroke in Postmenopausal Women
Shimbo D et al . – In postmenopausal women, greater visit–to–visit variability (VVV) of systolic blood pressure (SBP) was associated with increased risk of stroke, particularly in the lowest range of mean SBP.Methods
- The authors examined the association of VVV of blood pressure with stroke in 58228 postmenopausal women enrolled in the Women's Health Initiative.
- Duplicate blood pressure readings, which were averaged, were taken at baseline and at each annual visit.
- VVV was defined as the SD for the participant's mean systolic blood pressure (SBP) across visits (SD) and about the participant's regression line with SBP regressed across visits (SDreg).
- Over a median follow–up of 5.4 years, 997 strokes occurred.
- In an adjusted model including mean SBP over time, the hazard ratios (95% CI) of stroke for higher quartiles of SD of SBP compared with the lowest quartile (referent) were 1.39 (1.03–1.89) for quartile 2, 1.52 (1.13–2.03) for quartile 3, and 1.72 (1.28–2.32) for quartile 4 (P trend <0.001).
- The relation was similar for SDreg of SBP quartiles in a model that additionally adjusted for the temporal trend in SBP (P trend <0.001).
- The associations did not differ by stroke type (ischemic versus hemorrhagic).
- There was a significant interaction between mean SBP and SDreg on stroke with the strongest association seen below 120 mmHg.