Azusa Hara

Day-by-Day Variability of Blood Pressure and Heart Rate at Home as a Novel Predictor of Prognosis: The Ohasama Study

Day-by-day blood pressure and heart rate variability defined as within-subject SDs of home measurements can be calculated from long-term self-measurement. We investigated the prognostic value of day-by-day variability in 2455 Ohasama, Japan, residents (baseline age: 35 to 96 years; 60.4% women). Home blood pressure and heart rate were measured once every morning for 26 days (median). A total of 462 deaths occurred over a median of 11.9 years, composing 168 cardiovascular deaths (stroke: n=83; cardiac: n=85) and 294 noncardiovascular deaths. Using Cox regression, we computed hazard ratios while adjusting for baseline characteristics, including blood pressure and heart rate level, sex, age, obesity, current smoking and drinking habits, history of cardiovascular disease, diabetes mellitus, hyperlipidemia, and treatment with antihypertensive drugs. An increase in systolic blood pressure variability of +1 between-subject SD was associated with increased hazard ratios for cardiovascular (1.27; P=0.002) and stroke mortality (1.41; P=0.0009) but not for cardiac mortality (1.13; P=0.26). Conversely, heart rate variability was associated with cardiovascular (1.24; P=0.002) and cardiac mortality (1.30; P=0.003) but not stroke mortality (1.17; P=0.12). Similar findings were observed for diastolic blood pressure variability. Additional adjustment of heart rate variability for systolic blood pressure variability and vice versa produced confirmatory results. Coefficient of variation, defined as within-subject SD divided by level of blood pressure or heart rate, displayed similar prognostic value. In conclusion, day-by-day blood pressure variability and heart rate variability by self-measurement at home make up a simple method of providing useful clinical information for assessing cardiovascular risk.

Prediction of Stroke by Home “Morning” Versus “Evening” Blood Pressure Values: The Ohasama Study

Predictive power of self-measured blood pressure at home (home BP) for cardiovascular disease risk has been reported to be higher than casual-screening BP. However, the differential prognostic significance of home BP in the morning (morning BP) and in the evening (evening BP), respectively, has not been elucidated. In the Ohasama study, 1766 subjects (≥40 years) were followed up for an average of 11 years. The predictive power for stroke incidence of evening BP was compared with that of morning BP as continuous variables. The Cox regression model demonstrated that evening BP and morning BP predicted future stroke risk equally. Subjects were also assigned to 1 of 4 categories based on home BP. In this analysis, stroke risk in morning hypertension ([HT] morning BP ≥135/85 mm Hg and evening BP <135/85 mm Hg; relative hazard (RH): 2.66; 95% CI:1.64 to 4.33) and that in sustained HT(morning BP and evening BP ≥135/85 mm Hg; RH: 2.38; 95% CI: 1.65 to 3.45) was significantly higher than that in normotension (morning BP and evening BP <135/85 mm Hg). The risk in morning HT was more remarkable in subjects taking antihypertensive medication (RH: 3.55; 95% CI: 1.70 to 7.38). Although the risk in evening HT (morning BP <135/85 mm Hg and evening BP ≥135/85 mm Hg) was higher than that in normotension, the differences were not significant. In conclusion, morning BP and evening BP provide equally useful information for stroke risk, whereas morning HT, which indicates HT specifically observed in the morning, might be a good predictor of stroke, particularly among individuals using anti-HT medication.

Detection of carotid atherosclerosis in individuals with masked hypertension and white-coat hypertension by self-measured blood pressure at home: the Ohasama study.

Objective To investigate carotid atherosclerosis in individuals with masked hypertension (MHT) and white-coat hypertension (WCHT) in a general population. Methods Self-measurement of blood pressure at home (HBP) and casual blood pressure (CBP) measurements were recorded in 812 individuals aged at least 55 years (mean 66.4 years) from the general Japanese population. The intima–media thickness (IMT) of the near and far wall of both common carotid arteries was measured and averaged. The relationships between carotid atherosclerosis (IMT and plaque) and the four blood pressure groups (sustained normal blood pressure: HBP < 135/85 mmHg, CBP < 140/90 mmHg; WCHT: HBP < 135/85 mmHg, CBP ≥ 140/90 mmHg; MHT: HBP ≥ 135/85 mmHg, CBP < 140/90 mmHg; sustained hypertension: HBP ≥ 135/85 mmHg, CBP ≥ 140/90 mmHg) were examined using multivariate analysis adjusted for possible confounding factors. Results Adjusted IMT in individuals with sustained hypertension [0.77 mm; 95% confidence interval (CI) 0.75 to 0.79 mm] and MHT (0.77 mm; 95% CI 0.73 to 0.80 mm) was significantly greater than in those with sustained normal blood pressure (0.71 mm; 95% CI 0.69 to 0.72 mm) and WCHT (0.72 mm; 95% CI 0.71 to 0.74 mm) (P < 0.0001). The odds ratios for the presence of plaques in all four groups were similar to the trends in IMT. Conclusions Our findings imply that CBP measurements alone are insufficient to distinguish individuals at high risk of carotid atherosclerosis from those at low risk. However, these individuals do have distinct HBP measurements, suggesting that HBP measurement could become a valuable tool for predicting carotid atherosclerosis.

Prognostic significance of night-time, early morning, and daytime blood pressures on the risk of cerebrovascular and cardiovascular mortality: the Ohasama Study.

Objective To clarify whether high blood pressure (BP) at a particular time of day is associated with cerebrovascular and cardiovascular mortality risk. Methods Cerebrovascular and cardiovascular mortality in 1360 individuals aged 40 years and older in Ohasama, Japan, was followed for an average of 10.6 years. We used 2-h moving averages of the BP (a total of 24 average BP measurements for two consecutive hours based on four BP readings taken every 30 min) to compare the predictive power of BP taken during a 24-h period given the same number of measurements. The associations between cerebrovascular and cardiovascular mortality risk and the 2-h moving averages of systolic blood pressure (2 h-SBP) recorded over 24 h were analysed using a Cox proportional hazards model after adjusting for possible confounding factors. Results The total cerebrovascular and cardiovascular mortality risk was significantly associated with elevated 2 h-SBP recorded during the night and early morning periods. Haemorrhagic stroke mortality was significantly associated with elevated daytime 2 h-SBP. Cerebral infarction mortality and heart disease mortality were significantly associated with elevated night-time 2 h-SBP. Conclusion High BP at different times of day were associated with different subtypes of cerebrovascular and cardiovascular mortality risk.

Home Blood Pressure Variability as Cardiovascular Risk Factor in the Population of Ohasama

Blood pressure variability based on office measurement predicts outcome in selected patients. We explored whether novel indices of blood pressure variability derived from the self-measured home blood pressure predicted outcome in a general population. We monitored mortality and stroke in 2421 Ohasama residents (Iwate Prefecture, Japan). At enrollment (1988–1995), participants (mean age, 58.6 years; 60.9% women; 27.1% treated) measured their blood pressure at home, using an oscillometric device. In multivariable-adjusted Cox models, we assessed the independent predictive value of the within-subject mean systolic blood pressure (SBP) and corresponding variability as estimated by variability independent of the mean, difference between maximum and minimum blood pressure, and average real variability. Over 12.0 years (median), 412 participants died, 139 of cardiovascular causes, and 223 had a stroke. In models including morning SBP, variability independent of the mean and average real variability (median, 26 readings) predicted total and cardiovascular mortality in all of the participants (P⩽0.044); variability independent of the mean predicted cardiovascular mortality in treated (P=0.014) but not in untreated (P=0.23) participants; and morning maximum and minimum blood pressure did not predict any end point (P≥0.085). In models already including evening SBP, only variability independent of the mean predicted cardiovascular mortality in all and in untreated participants (P⩽0.046). The R 2 statistics, a measure for the incremental risk explained by adding blood pressure variability to models already including SBP and covariables, ranged from <0.01% to 0.88%. In a general population, new indices of blood pressure variability derived from home blood pressure did not incrementally predict outcome over and beyond mean SBP.

Diabetes mellitus and cancer risk: pooled analysis of eight cohort studies in Japan.

Although a growing body of evidence suggests a link between diabetes and cancer, it is not clear whether diabetes independently increases the risk of cancer. We conducted a comprehensive assessment of the association between pre‐existing diabetes and total and site‐specific cancer risk based on a pooled analysis of eight cohort studies in Japan (>330 000 subjects). We estimated a summary hazard ratio by pooling study‐specific hazard ratios for total and site‐specific cancer by using a random‐effects model. A statistically increased risk was observed for cancers at specific sites, such as colon (hazard ratio; HR = 1.40), liver (HR = 1.97), pancreas (HR = 1.85) and bile duct (HR = 1.66; men only). Increased risk was also suggested for other sites, and diabetes mellitus was associated with an overall 20% increased risk in total cancer incidence in the Japanese population. The association between these two diseases has important implications for reiterating the importance of controlling lifestyle factors and may suggest a possible strategy for cancer screening among patients with diabetes. Studies continuously investigating the risk factors for diabetes are also important.

Ambulatory blood pressure, blood pressure variability and the prevalence of carotid artery alteration: the Ohasama study

Objectives To investigate the association between ambulatory blood pressure (BP) variables (level, short-term variability, circadian variation and morning pressor surge) and carotid artery alteration in a general population. Methods We measured ambulatory BP every 30 min in 775 participants (mean age 66.2 ± 6.2 years, 68.8% women) from the Japanese general population. Short-term BP variability during the daytime and night-time were estimated as within-subject standard deviation of daytime and night-time BP, respectively. Circadian BP variation was calculated as the percentage decline in nocturnal BP. Morning pressor surge was defined as morning BP minus pre-waking BP. The extent of carotid artery alteration was evaluated as the average of common carotid intima–media thickness (IMT) and the presence of focal carotid plaque. Results Daytime and night-time BP values were more closely associated with carotid artery alteration than casual BP. With mutual adjustment for daytime and night-time BP, the latter (P < 0.0001) was more closely associated with IMT, which represents diffuse arterial thickening and arteriosclerosis, than daytime BP (P = 0.2). Night-time systolic BP variability was positively associated with carotid plaque (focal atherosclerotic lesions) independently of possible confounding factors, including night-time systolic BP (P = 0.01). A diminished nocturnal decline in systolic BP was associated with a greater IMT after adjustment for confounding factors (P = 0.03). A morning pressor surge was not associated with carotid artery alteration. Conclusion Ambulatory BP levels and BP variability were closely associated with carotid artery alteration, suggesting that these parameters are independent risk factors or predictors of carotid artery alteration.

Cost-effectiveness of the introduction of home blood pressure measurement in patients with office hypertension

Objective Cost-effectiveness of hypertension treatment is an important social and medical issue in Western as well as in Eastern countries, including Japan. Home blood pressure (HBP) measurements have a stronger predictive power for cardiovascular events than casual clinic blood pressure (CBP) measurements. Therefore, the introduction of HBP measurement for the diagnosis and treatment of hypertension should lead to a decrease in medical expenditure. This study presents calculations of the cost savings likely to take place when HBP is implemented for newly detected hypertensive subjects in Japan. Design and methods We estimate the cost savings from the perspective of a Japanese healthcare system. To estimate the costs associated with changing from CBP to HBP measurement as the diagnostic tool, we constructed a simulation model using data from the Ohasama study. These calculations are based on current estimates for cost of treatment, prevalence of white-coat hypertension at baseline, and varying the incidence of new hypertension after the initial screening. Results When HBP measurement is not incorporated into the diagnostic process, the medical cost is estimated at US

Association of arterial stiffness with silent cerebrovascular lesions: the Ohasama study.

10.89 million per 1000 subjects per 5 years. When HBP measurement is incorporated, the medical cost is estimated at US

Predictive value of ambulatory heart rate in the Japanese general population: the Ohasama study.

9.33 million per 1000 subjects per 5 years. The reductions in medical costs vary from US