Wallace, Erin R.

Introduction: Recent reports have linked visit-to-visit blood pressure (BP) variability to risk of mortality and stroke, independent of the effect of mean BP level. We sought to confirm these findings in the Cardiovascular Health Study (CHS), a cohort study of cardiovascular risk factors. Hypothesis: Variability in visit-to-visit SBP, defined as intraindividual SBP SD, is directly associated with risk of mortality, myocardial infarction (MI), and stroke, independent of intraindividual SBP mean and trend over time. Methods: Participants from CHS were eligible if they attended their first five annual clinic visits and did not have stroke, MI, or death by the 5th visit (N=3513). Follow-up started at the 5th visit and extended through June 2008. Analyses were further restricted to subjects who used no antihypertensive medications during the entire 5-year baseline period (non-users, n=1570) and subjects who used the same antihypertensive regimen during that time (users, n=978). Intraindividual SBP variables were defined using each subject’s 5-visit BPs. Cox proportional hazards models estimated adjusted hazard ratios (HR) per standard deviation (SD) increase in intraindividual SD (iSD) SBP or intraindividual mean (iMean) SBP. Results were stratified on medication use or non-use. Results: Participants’ mean age was 71 years, 42% were men, and 95% were white. Mean(SD) of iSD SBP was 9.8(4.6) mmHg for anti-hypertensive medications non-users and 12.0(6.0) mmHg for users. iMean SBP was significantly associated with all 3 outcomes among non-users and with stroke among users (table). iSD SBP was significantly associated with mortality in all participants and with MI among non-users; associations for stroke were not significant. Conclusion: Long-term visit-to-visit SBP variability may be an important determinant of MI and mortality risk in the elderly. Results for stroke are not consistent with other, previous reports. More research is needed to determine the clinical implications.