Increased home blood pressure (BP) variability seems to be associated with cardiovascular disease, but the lack of operational thresholds limits its clinical application. Our aim was to define outcome-driven thresholds for day-to-day home BP variability in the general population.Design and Method:
The study population consisted of 6312 community-dwelling participants from Ohasama, Japan; Tsurugaya, Japan; Didima, Greece; and Finland. The participants were divided into ten groups by deciles of home BP variability, defined as the coefficient of variation (CV) of the first measurements of each day between 5:00 and 12:00 AM to account for between-cohort differences in measurement protocols. Association between BP variability and cardiovascular mortality or cardiovascular events was assessed using Cox models adjusted for home systolic or diastolic BP, cohort, sex, age, body mass index, smoking status, diabetes status, use of antihypertensive medication, total serum cholesterol and history of cardiovascular disease.Results:
Home blood pressure was measured on 22.6 ± 7.6, 15.0 ± 10.4, 3.0 ± 0.12 and 6.8 ± 0.6 days in Ohasama, Tsurugaya, Didima and Finland, respectively. During a mean follow-up of 9.3 ± 3.7 years, 306 and 720 cardiovascular deaths and events occurred, respectively. 1-SD increase in systolic/diastolic home BP variability was associated with cardiovascular mortality (Hazard ratio 1.18/1.22 [95% confidence interval 1.06 − 1.31/1.10−1.34], p = 0.003/ < 0.0001) and cardiovascular events (Hazard ratio 1.15/1.17 [95% confidence interval 1.07−1.23/1.09−1.26], p = 0.0001/<0.0001). Risk of cardiovascular deaths and events was significantly increased in the 10th decile of systolic/diastolic BP variability (CV > 10.7/12.6), as compared with the average risk in the whole population (Table). The results were similar regardless of antihypertensive treatment status.Conclusions:
Home BP variability appears to be an independent risk factor for cardiovascular mortality and morbidity. Cardiovascular risk seems to increase when the systolic/diastolic CV of day-to-day home BP is greater than 10.7/12.6. Our current findings could inform guidelines and help clinicians in diagnosing and managing patients.