Factors affecting the difference between screening and home blood pressure measurements: the Ohasama Study

Prediction Models for the 5- and 10-Year Incidence of Home Morning Hypertension: The Ohasama Study

BACKGROUND

We aimed to develop risk prediction models for new-onset home morning hypertension.

METHODS

We followed up 978 participants without home hypertension in the general population of Ohasama, Japan (men: 30.1%, age: 53.3 years). The participants were divided into derivation (n = 489) and validation (n = 489) cohorts by their residential area. The C-statistics and calibration plots were assessed after the 5- or 10-year follow-up.

RESULTS

In the derivation cohort, sex, age, body mass index, smoking, office systolic blood pressure (SBP), and home SBP at baseline were selected as significant risk factors for new-onset home hypertension (≥135/85 mm Hg or the initiation of antihypertensive treatment) using the Cox model. In the validation cohort, Harrell's C-statistic for the 5-/10-year home hypertension was 0.7637 (0.7195-0.8100)/0.7308 (0.6932-0.7677), when we used the full model, which included the significant risk factors in the derivation cohort. The calibration test revealed good concordance between the observed and predicted 5-/10-year home hypertension probabilities (P ≥ 0.19); the regression slope of the observed probability on the predicted probability was 1.10/1.02, and the intercept was -0.04/0.06, respectively. A model without home SBP was also developed; for the 10-year home hypertension risk, the calibration test revealed a good concordance (P = 0.19) but Harrell's C-statistic was 0.6689 (0.6266-0.7067).

CONCLUSIONS

The full model revealed good ability to predict the 5- and 10-year home morning hypertension risk. Although the model without home SBP is acceptable, the low C-statistic implies that home BP should be measured to predict home morning hypertension precisely.

Comparison among research, home, and office blood pressure measurements for pregnant women: The TMM BirThree Cohort Study

Blood pressure (BP) measurements of pregnant women have been collected in offices and at home for previous research. However, it remains uncertain whether there is difference between research BP, defined as BP measured for the purpose of epidemiological research and BP measured at home or in an office. Therefore, the present study aimed to compare research BP with home and unstandardized office BP. Research, home, and office BP were measured among pregnant women who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study). Research BP was measured twice at our research center while the participant was seated and after resting for 1-2 minutes. Research, home, and office BP were compared and agreement among the values was assessed. Differences among research, home, and office BP values and possible factors affecting differences were analyzed. Among 656 pregnant women, the mean (± standard deviations) research systolic (S), diastolic (D) BP, home SBP, home DBP office SBP, and office DBP were 103.8 ± 8.5, 61.8 ± 7.3, 104.4 ± 9.2, 61.2 ± 6.8, 110.5 ± 10.8, and 63.8 ± 8.7mmHg, respectively. Research SBP value was lower than home value (P = .0072; difference between mean research and home BP: -0.61 ± 7.8 mmHg). Research SBP and DBP values were lower than office values (P < .0001 for both SBP and DBP; means ± standard deviations of differences between research and office BP: 6.7 ± 10.1 and 2.0 ± 8.5 mmHg for SBP and DBP, respectively). In conclusion, when research BP is measured under conditions controlled, research BP can give close values to home BP for pregnant women.

Differences between home blood pressure and strictly measured office blood pressure and their determinants in Japanese men

Conventional office blood pressure (OBP) and home blood pressure (HBP) measurements are often inconsistent. The purpose of this research was (1) to test whether strictly measured OBP values with sufficient rest time before measurement (st-OBP) is comparable to HBP at the population level and (2) to ascertain whether there are particular determinants for the difference between HBP and st-OBP at the individual level. Data from a population-based group of 1056 men aged 40-79 years were analyzed. After a five-min rest, st-OBP was measured twice. HBP was measured after a 2-min rest every morning for seven consecutive days. To determine factors related to ΔSBP (HBP minus st-OBP measurements), multiple linear regression analyses and analyses of covariance were performed. While st-OBP and HBP were comparable (136.5 vs. 137.2 mmHg) at the population level, ΔSBP varied with a standard deviation of 13.5 mmHg. Smoking was associated with a larger ΔSBP regardless of antihypertensive usage, and BMI was associated with a larger ΔSBP in participants using antihypertensive drugs. The adjusted mean ΔSBP in the highest BMI tertile category was 4.6 mmHg in participants taking antihypertensive drugs. st-OBP and HBP measurements were comparable at the population level, although the distribution of ΔSBP was considerably broad. Smokers and obese men taking antihypertensive drugs had higher HBP than st-OBP, indicating that their blood pressure levels are at risk of being underestimated. Therefore, this group would benefit from the addition of HBP measurements.

Genome-wide association study for white coat effect in Japanese middle-aged to elderly people: The HOMED-BP study

BACKGROUND

White coat effect (WCE), the blood pressure (BP) difference between clinical and non-clinical settings, can lead to clinical problems such as misdiagnosis of hypertension. Etiology of WCE has been still unclear, especially from genetic aspects. The present article investigated association between genome-wide single nucleotide polymorphisms (SNPs) and WCE in patients with essential hypertension.

METHODS

The present cross-sectional analyses were based on 295 Japanese essential hypertensive outpatients aged ≧40 years enrolled in randomized control study, Hypertension Objective Treatment Based on Measurement by Electrical Devices of Blood Pressure (HOMED-BP) study, who were not taking antihypertensive medications before the randomization. Home and clinic BP were measured. WCE was defined by subtracting home BP from clinic BP. Genotyping was conducted with 500K DNA microarray chips. Association between genome-wide SNPs and WCE were analyzed. For replication (p < 10^-4), we analyzed participants from Ohasama study who took no antihypertension medications and whose SNPs were collected.

RESULTS

Genome-wide SNPs were not significantly associated with WCE of systolic and diastolic BP after corrections of multiple comparisons (p < 2 × 10^-7). We found suggestive SNPs associated with WCE of systolic and diastolic BP (p < 10^-4). However, the consistent results were not obtained in the replication study.

CONCLUSION

The present article showed no significant association between genome-wide SNPs and WCE. Since there were several suggestive SNPs associated with WCE, the present study warrants a further study with bigger sample size for investigating the genetic influence on WCE.

Prevalence and Determinants of Masked Hypertension Among Black Nigerians Compared With a Reference Population

Hitherto, diagnosis of hypertension in sub-Saharan Africa was largely based on conventional office blood pressure (BP). Data on the prevalence of masked hypertension (MH) in this region is scarce. Among individuals with normal office BP (<140/90 mm Hg), we compared the prevalence and determinants of MH diagnosed with self-monitored home blood pressure (≥135/85 mm Hg) among 293 Nigerians with a reference population consisting of 3615 subjects enrolled in the International Database on Home Blood Pressure in Relation to Cardiovascular Outcomes. In the reference population, the prevalence of MH was 14.6% overall and 11.1% and 39.6% in untreated and treated participants, respectively. Among Nigerians, the prevalence standardized to the sex and age distribution of the reference population was similar with rates of 14.4%, 8.6%, and 34.6%, respectively. The mutually adjusted odds ratios of having MH in Nigerians were 2.34 (95% confidence interval, 1.39–3.94) for a 10-year higher age, 1.92 (1.11–3.31) and 1.70 (1.14–2.53) for 10- or 5-mm Hg increments in systolic or diastolic office BP, and 3.05 (1.08–8.55) for being on antihypertensive therapy. The corresponding estimates in the reference population were similar with odds ratios of 1.80 (1.62–2.01), 1.64 (1.45–1.87), 1.13 (1.05–1.22), and 2.84 (2.21–3.64), respectively. In conclusion, MH is as common in Nigerians as in other populations with older age and higher levels of office BP being major risk factors. A significant proportion of true hypertensive subjects therefore remains undetected based on office BP, which is particularly relevant in sub-Saharan Africa, where hypertension is now a major cause of death.

Frequency, Awareness, Treatment and Control of Hypertension in the over 40 Population of Erzincan

To determine distribution of blood pressure (BP) and prevalence, awareness, treatment and control of hypertension in 5 primary health care centers of Erzincan. A population-based cross-sectional survey was carried out in January - May 2009. A two-stage sampling method was used to select a sample of adult population 40 and over years of age. The total number of participants was 1570. Data were collected by face-to-face interview technique in the primary health care setting. Main outcome measures; mean systolic and diastolic blood pressures, distribution of blood pressure, prevalence of hypertension (mean systolic BP≥140 mmHg or mean diastolic BP ≥90 mmHg, or previously diagnosed and/or taking antihypertensive drugs) awareness, treatment and control of hypertension were assessed. The overall hypertension prevalence was 67.0% in the study sample and 77.4% of them were aware of their hypertension and received a pharmacologic treatment. Of the patients who were aware of the disease, 51.8% use drug treatment. Of the patients who had a drug treatment, 33.9 % were under control in terms of blood pressure. Our data indicate that hypertension is a highly prevalent but inadequately managed health problem in Erzincan. There is an urgent need for population-based strategies to improve prevention, early detection, and control of hypertension.

Treated and untreated hypertension, hospitalization, and medical expenditure: an epidemiological study in 314622 beneficiaries of the medical insurance system in Japan

OBJECTIVE

This study investigated the effect of hypertension on hospitalization risk and medical expenditure according to treatment status in a Japanese population.

METHODS

A total of 314 622 beneficiaries of the medical insurance system in Japan, aged 40-69 years, without a history of cardiovascular, cerebrovascular, or end-stage renal disease were classified into seven blood pressure categories. These categories were used to compare the risk of undergoing hospitalization in the 1 year after the baseline survey and to examine the percentage of inpatient medical expenditure attributable to overall hypertension relative to total medical expenditure in the study population.

RESULTS

During the follow-up period, 6.6% of men and 5.1% of women were hospitalized. In men and women aged 40-54 years, cases of hypertension, especially grade 3 untreated hypertension, led to more frequent hospitalization, compared with optimal blood pressure. Individuals who were hospitalized, especially long-term, incurred considerably higher medical expenditure compared with those who were not hospitalized, regardless of their hypertension status. In women aged 55-69 years, there was little variation in hospitalization risk across blood pressure categories. The inpatient medical expenditure attributable to overall hypertension represented 7.2 and 6.9% of the total medical expenditure for men aged 40-54 and 55-69 years, whereas it represented 2.8 and 3.8% for women, respectively.

CONCLUSION

Although cases of hypertension were an economic burden especially in men, grade 3 untreated hypertension was more likely to incur extremely high medical expenditure as a result of hospitalization, compared with other cases.

Blood pressure measurement: clinic, home, ambulatory, and beyond

Blood pressure traditionally has been measured in the clinic setting using the auscultatory method and a mercury sphygmomanometer. Technologic advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24-hour ambulatory blood pressures have improved our ability to evaluate the risk of target-organ damage and hypertension-related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are 2 of the newer methods for assessing blood pressure and hypertension-related target-organ damage.

Relationship of dysregulation of glucose metabolism with white-coat hypertension: the Ohasama study

Characteristics of glucose metabolism in subjects with white-coat hypertension (WCHT) have not been fully investigated. The purpose of this study was to determine the relationship between glucose metabolism and WCHT on the basis of blood pressure (BP) at home (HBP) in the general population. Participants were from Ohasama, a rural Japanese community, and included 466 residents (mean age, 61.0 years) who had no history of diabetes mellitus. HBP and oral glucose tolerance test values were measured. Participants were classified into four groups on the basis of their HBP and casual-screening BP (CBP) values: normotension (NT) (HBP<135/85 mm Hg, CBP<140/90 mm Hg); WCHT (HBP<135/85 mm Hg, CBP>/=140/90 mm Hg); masked hypertension (HBP>/=135/85 mm Hg, CBP<140/90 mm Hg); or sustained hypertension (SHT) (HBP>/=135/85 mm Hg, CBP>/=140/90 mm Hg). The relationships between glucose metabolism and BP among the four groups were examined using multivariate analysis adjusted for possible confounding factors. Factors in relation to glucose metabolism, such as fasting glucose level, 2-h postchallenge glucose level and homeostasis model assessment-insulin resistance index, were significantly higher in subjects with WCHT and SHT than in those with NT (all P<0.03). When men and women were analyzed separately, these relationships were more pronounced in women. Our results suggest that dysregulation of glucose metabolism in WCHT might contribute to the increase in the long-term cardiovascular risk among the general population.

Masked hypertension: different blood pressure measurement methodology and risk factors in a working population

OBJECTIVES

To estimate the prevalence of masked hypertension when the same ambulatory device is used for both manual and ambulatory blood pressure measurements and to measure associations with lifestyle risk factors in a working population.

METHODS

White-collar workers were recruited from three public organizations. Blood pressure was measured at the workplace using Spacelabs 90207 for manual measurements (mean of the first three readings taken by a trained assistant) followed by ambulatory measurements (mean of every other reading obtained during the working day). Masked hypertension was defined as manual blood pressure measurement of less than 140/90 mmHg and ambulatory blood pressure measurement of at least 135/85 mmHg. Smoking, alcohol intake, BMI and leisure physical activity were also assessed.

RESULTS

Blood pressure measurements were obtained from 2370 workers (80% participation, 61% women; mean age = 44 years). Masked hypertension was diagnosed in 15.02% of the participants. The prevalence was higher in men [adjusted odds ratio (OR) = 2.38, 95% confidence interval (CI) = 1.86-3.05]. The prevalence in men increased with age (adjusted OR = 2.08 for 40-49 years, 95% CI = 1.33-3.26 and adjusted OR = 1.91 for > or =50 years, 95% CI = 1.20-3.04) and BMI (adjusted OR = 1.78 for BMI > or = 27, 95% CI = 1.21-2.64). The prevalence in women increased with BMI (adjusted OR = 1.65 for BMI > or =27, 95% CI = 1.14-2.39) and alcohol intake (adjusted OR = 2.12 for at least six drinks per week, 95% CI = 1.34-3.35).

CONCLUSION

Masked hypertension is frequent and still present when blood pressure is measured out of the office, using the same device for manual and ambulatory measurements. Sex, age, BMI and alcohol intake are associated with masked hypertension.

Does blood pressure change in treated hypertensive patients depending on whether it is measured by a physician or a nurse?

OBJECTIVES

To determine whether there are differences between blood pressure (BP) measured by the nurse (NBP), BP measured by the physician (PBP) and self-measured BP in treated hypertensive patients and, if found, to evaluate their clinical importance.

METHOD

An observational study is carried out with hypertensive patients recruited from two village-based community health centres in Catalonia (Spain) serving an area with a total population of 2800 inhabitants. All patients treated for hypertension visiting the health centre on a specific day of the week and during the same timetable between October 2000 and May 2001 were included.

RESULTS

The difference between physician-systolic BP and nurse-systolic BP was 5.16 mmHg (95% CI 2.62-7.7; p<0.001). The difference between physician-systolic BP and self-measured systolic BP was 4.67 mmHg (95% CI 0.89-8.44; p=0.016). The differences between nurse-systolic BP and self-measured systolic BP were not significant (0.49 mmHg; 95% CI 3.71-2.71; p=0.758). With regards to diastolic BP, no significant differences were found between the different ways of measurement. NBP gave the following values: sensitivity (Sn) of 92% and specificity (Sp) of 60%; positive predictive value (PPV) of 65.7% and negative predictive value (NPV) of 90% with a positive coefficient of probability (CP+) of 2.3 and a negative coefficient of probability (CP-) of 0.133. PBP gave the following results: Sn=72%; Sp=66.7%; PPV=64.3%; NPV=74.1%; CP+=2.16 and CP- = 0.420.

CONCLUSION

Systolic BP measured by the nurse in treated hypertensive patients is significantly lower than the readings obtained by the physician, and are almost identical to ambulatory BP monitoring. Blood pressure determination by the nurse is desirable not only for diagnosis but also to evaluate the level of control of blood pressure during the follow-up of treated hypertensive patients.

Determinants of negative white-coat effect in treated hypertensive patients: the Jichi Morning Hypertension Research (J-MORE) study

BACKGROUND

The negative white-coat effect (WCE), a phenomenon in which out-of-office blood pressure (BP) is higher than clinic BP, has not been well examined, unlike the WCE.

METHODS

As part of the Jichi Morning Hypertension Research study, in which clinic and home BP were measured in 969 hypertensive outpatients, 405 patients with normal clinic BP were separately analyzed. Clinic BP was measured on two different occasions, and home BP was measured twice in the morning and twice in the evening for three consecutive days. Clinic and home BP were each averaged from all readings, and negative WCE was defined as clinic systolic BP (SBP) lower than home SBP.

RESULTS

Negative WCE was observed in 324 (33%) of the patients overall and in 173 (42%) of the patients with controlled BP (clinic BP < 140/90 mm Hg). In multiple logistic regression analysis adjusting for covariates including home SBP and pulse rate, negative WCE was correlated with older age (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.01-1.06) and male gender (OR 1.08, 95% CI 1.01-1.14) in overall subjects. Among patients with well-controlled clinic BP, negative WCE was significantly correlated with the presence of ischemic heart disease (OR 1.17, 95% CI 1.04-1.31). The association of negative WCE with age and male gender remained significant under stringent criteria (negative WCE < -10.2 mm Hg (the mean -1 s.d.)).

CONCLUSIONS

Negative WCE remaining even after clinic BP is controlled may be related to cardiovascular risk factors such as older age, male gender, and a history of ischemic heart disease.

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$10.89 million per 1000 subjects per 5 years. When HBP measurement is incorporated, the medical cost is estimated at US$9.33 million per 1000 subjects per 5 years. The reductions in medical costs vary from US$674,000 to US$2.51 million per 1000 subjects per 5 years for treatment of hypertension, when sensitivity analysis is performed.

CONCLUSIONS

The introduction of HBP measurement for the treatment of hypertension is very useful for reducing medical costs.

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 >or= 140/90 mmHg; MHT: HBP >or= 135/85 mmHg, CBP < 140/90 mmHg; sustained hypertension: HBP >or= 135/85 mmHg, CBP >or= 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.

Introversion associated with large differences between screening blood pressure and home blood pressure measurement: The Ohasama study

OBJECTIVE

To explore the effect of personality on screening blood pressures measured in clinical settings and home blood pressure measurements.

METHODS

From 1997 to 1999, 699 participants underwent screening and home blood pressure measurements and completed the Japanese version of the short-form Eysenck personality questionnaire. An increased screening blood pressure was defined as screening blood pressure > or = 140/90 mmHg and an increased home blood pressure was defined as home blood pressure > or = 135/85 mmHg.

RESULTS

Participants with lower extroversion scores (i.e., introversion) showed a greater difference between screening and home systolic blood pressure. The association between introversion and differences was statistically significant, even after adjustment for other possible factors (younger age, female, wide screening pulse pressure, never smoked, and no antihypertensive medication). The adjusted means of SBP differences were 7.3 and 4.4 mmHg among the lowest and highest extroversion quartiles, respectively (P for trend = 0.02). Other personality scores (psychoticism or neuroticism) were not associated with screening and home blood pressure differences. The incorporation of an extroversion score in the basic model consisting of the above factors that affected the difference between screening and home blood pressure slightly improved the prediction of a high home blood pressure. The area under the receiver operating characteristic curve increased by 0.037 among participants with high screening blood pressure and 0.006 for those with normal screening blood pressure compared with the basic model.

CONCLUSION

Physicians may need to be aware of 'introverted' patients who have high blood pressure in clinic settings, because they have the potential for 'white-coat' hypertension.

The economic impact of the introduction of home blood pressure measurement for the diagnosis and treatment of hypertension

OBJECTIVES

To investigate the economic consequences resulting from introduction of home blood pressure measurement in diagnosis of hypertension instead of casual clinic blood pressure measurement.

METHODS

We constructed a decision tree model using data from the Ohasama study and a Japanese national database. The Ohasama study provided the prognostic value of home blood pressure as compared with clinic blood pressure measurement.

RESULTS

It is predicted that the use of home blood pressure for hypertension diagnosis results in a saving of 9.30 billion US dollars (1013.6 billion yen) in hypertension-related medical costs in Japan. Most of this was attributable to medical costs saved by avoiding the start of treatment for untreated individuals who were diagnosed as hypertensive by clinic blood pressure but whose blood pressures were in the normal range when based on home blood pressure; that is, the so called white-coat hypertension. Furthermore, it could be expected that adequate blood pressure control mediated by the change in the diagnostic method from clinic to home blood pressure measurement would improve the prognosis for hypertension. We estimated that the prevention of hypertensive complications resulted in a reduction of annual medical costs by 28 million US dollars (3.0 billion yen). In addition, stroke prevention due to adequate blood pressure control based on home blood pressure measurement reduced annual long-term care costs by 39 million US dollars (4.2 billion yen). A per-person break-even cost for introducing home blood pressure monitoring was calculated as 409 US dollars (44,580 yen).

CONCLUSIONS

The introduction of home blood pressure measurement for the diagnosis and treatment of hypertension would be very effective to save costs.

Isolated uncontrolled hypertension at home and in the office among treated hypertensive patients from the J-HOME study

OBJECTIVES

To evaluate the current status of blood pressure (BP) control as measured at home and in the office, as well as to clarify and compare the prevalence and characteristics of isolated uncontrolled hypertension as measured at home (home hypertension) and in the office (office hypertension).

DESIGN

A cross-sectional study.

SETTING

Primary care offices in Japan.

PARTICIPANTS

A sample of 3400 patients with essential hypertension (mean age, 66 years; males, 45%) receiving antihypertensive treatment.

RESULTS

Overall, the mean home systolic BP (SBP)/diastolic BP (DBP) was 140/82 mmHg, and the mean office SBP/DBP was 143/81 mmHg. Of the 3400 subjects, 19% had controlled hypertension (home SBP/DBP < 135/85 mmHg and office SBP/DBP < 140/90 mmHg), 23% had isolated uncontrolled home hypertension (home SBP/DBP >/= 135/85 mmHg and office SBP/DBP < 140/90 mmHg), 15% had isolated uncontrolled office hypertension (home SBP/DBP < 135/85 mmHg and office SBP/DBP < 140/90 mmHg), and 43% had uncontrolled hypertension (home SBP/DBP >/= 135/85 mmHg and office SBP/DBP >/= 140/90 mmHg). Compared to controlled hypertension, factors associated with isolated uncontrolled home hypertension included obesity, relatively higher office SBP, habitual drinking, and the use of two or more prescribed antihypertensive drugs. Compared to uncontrolled hypertension, factors associated with isolated uncontrolled office hypertension included female gender, lower body mass index, and relatively lower office SBP.

CONCLUSIONS

The use of all four, three of four, or all three predictive factors might be useful for the clinician to suspect isolated uncontrolled home or office hypertension.

How many times should blood pressure be measured at home for better prediction of stroke risk? Ten-year follow-up results from the Ohasama study

OBJECTIVE

To determine the optimum number of blood pressure self-measurements taken at home (home blood pressure) in relation to their predictive value for stroke risk.

METHODS

We obtained more than 14 measurements of home blood pressure from 1491 people aged >or=40 years without a history of stroke in the general population in Japan, and followed them up after a mean period of 10.6 years. The prognostic significance of blood pressure for stroke risk was examined using the Cox proportional hazards regression model, which was adjusted for possible confounding factors.

RESULTS

The predictive value of home blood pressure increased progressively with the number of measurements, showing the highest predictive value with the average of whole measurements (mean = 25 measurements, 35% increase in the risk of stroke per 10 mmHg elevation in blood pressure). The initial home blood pressure values (one measurement) showed a significantly greater relation with stroke risk than conventional blood pressure values (mean of two measurements) (19/8% increase in the risk of stroke per 10 mmHg elevation in initial home/conventional systolic blood pressure values, respectively).

CONCLUSIONS

There was no threshold for the number of home blood pressure measurements within the range of 1-14 measurements for increasing the predictive power of stroke risk, suggesting that as many measurements as possible, preferably more than 14 measurements, is recommended for better prediction of stroke risk. It should be emphasized that home blood pressure has a stronger predictive power than does conventional blood pressure, even for a lower number of measurements.

High Blood Pressure in Acute Stroke and Subsequent Outcome

High blood pressure (BP) is common in acute stroke and might be associated with a poor outcome, although observational studies have given varying results. In a systematic review, articles were sought that reported both admission BP and outcome (death, death or dependency, death or deterioration, stroke recurrence, and hematoma expansion) in acute stroke. Data were analyzed by the Cochrane Review Manager software and are given as odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs). Altogether, 32 studies were identified involving 10 892 patients. When all data were included, death was significantly associated with an elevated mean arterial BP ([MABP] OR, 1.61; 95% CI, 1.12 to 2.31) and a high diastolic BP ([DBP] OR, 1.71; 95% CI, 1.33 to 2.48). Combined death or dependency was associated with high systolic BP ([SBP] OR, 2.69; 95% CI, 1.13 to 6.40) and DBP (OR, 4.68; 95% CI, 1.87 to 11.70) in primary intracerebral hemorrhage (PICH). Similarly, high SBP (+11.73 mm Hg; 95% CI, 1.30 to 22.16), MABP (+9.00 mm Hg; 95% CI, 0.92 to 17.08), and DBP (+6.00 mm Hg; 95% CI, 0.19 to 11.81) were associated with death or dependency in ischemic stroke. Combined death or deterioration was associated with a high SBP (OR, 5.57; 95% CI, 1.42 to 21.86) in patients with PICH. In summary, high BP in acute ischemic stroke or PICH is associated with subsequent death, death or dependency, and death or deterioration. Moderate lowering of BP might improve outcome. Acute BP lowering needs to be tested in 1 or more large, randomized trials.

Home Blood Pressure Is a Better Predictor of Carotid Atherosclerosis than Office Blood Pressure in Community-Dwelling Subjects

An increase in the thickness of the intima-media (IMT) of the carotid artery is associated with an increased risk of cardiovascular morbidity and mortality. Hypertension is one of the underlying mechanisms for the progression of carotid atherosclerosis. However, office blood pressure (BP) has been shown to have only a weak association with carotid IMT. Since self-measured home BP has less variation than office BP, home BP could be a better predictor of carotid atherosclerosis. To explore this hypothesis, we compared the relationships between carotid IMT and office BP or home BP in a community-dwelling population. One-hundred and one community residents, aged 50 years or older and not taking any medication, were enrolled in this study. Morning home BP was measured according to the guidelines of the Japanese Society of Hypertension. The results were recorded for 2 weeks and averaged. Carotid atherosclerosis was defined as IMT > or =0.80 mm, which corresponds to the first quartile. Home systolic BP showed a more significant association with carotid IMT (r=0.422, p <0.0001) than with office systolic BP (r=0.021, p=0.027). Logistic regression analysis for the presence of carotid atherosclerosis further showed that the relative risk of hypertension defined using home BP (> or =135/85 mmHg) was 6.3 (95% confidence interval [CI]: 2.0 to 19.6), while that using office BP was 1.5 (95% CI: 0.5 to 4.2). These results suggest that home BP is a better predictor of the development of carotid atherosclerosis than office BP.

Blood pressure control assessed by home, ambulatory and conventional blood pressure measurements in the Japanese general population: the Ohasama study

To assess blood pressure control in the Japanese population, we analyzed previously obtained measurements of conventional, home and ambulatory blood pressures in 1,174 subjects aged > or =40 in a Japanese community. On the basis of conventional blood pressure values and the use of antihypertensive medication, participants were classified as normotensive, untreated hypertensive and treated hypertensive subjects. When 140/90, 135/85 and 135/85 mmHg were used as the hypertension criteria for conventional, home and ambulatory blood pressure measurements, respectively, all three blood pressure values were higher in untreated and treated hypertensive subjects than in normotensive subjects. Among the treated hypertensive subjects, approximately half were classified as hypertensive not only by conventional blood pressure, but also by home or ambulatory measurements. Approximately 10% of the subjects defined as normotensive by conventional blood pressure measurement were classified as hypertensive by home or ambulatory measurements, whereas 60% of the untreated hypertensive subjects as defined by conventional blood pressure measurement had normal home or ambulatory blood pressure values. Therefore, we concluded that 1) the poor blood pressure control in treated hypertensive subjects was attributable not only to the white coat effect but also to inadequate control of blood pressure; and 2) a certain percentage of subjects were misclassified as hypertensive or normotensive by conventional blood pressure measurement.