Early influences on blood pressure: a study of children aged 5-7 years.

OBJECTIVE--To examine factors that influence blood pressure in children. DESIGN--Cross sectional study of children aged 5.0-7.0 years who had blood pressure measurements and for whom parental questionnaires were completed. SETTING--School based survey. SUBJECTS--3591 Children aged 5.0-7.5 years selected by stratified random sampling of primary schools in nine British towns (response rate 72%); 3591 were examined and their parental questionnaires were completed. Data were complete for birth rank in 3559, maternal age in 3542, maternal history of hypertension in 3524, and paternal history in 2633. RESULTS--Birth weight was inversely related to mean systolic blood pressure but only when standardised for current weight (weight standardised regression coefficient -1.83 mm Hg/kg (95% confidence interval -1.31 to -2.35). Mean diastolic pressure was similarly related to birth weight. Maternal age, birth rank, and a parental history of hypertension were all related to blood pressure. After standardisation for current weight a 10 year increase in maternal age was associated with a 1.0 mm Hg (0.4 to 1.6) rise in systolic pressure; first born children had systolic blood pressure on average 2.53 mm Hg (0.81 to 4.25) higher than those whose birth rank was greater than or equal to 4; and a maternal history of hypertension was associated with a systolic pressure on average 0.96 mm Hg (0.41 to 1.51) higher than in those with no such history. The effects described were largely independent of one another and of age and social class. The relation for birth rank was, however, closely related to that for family size. CONCLUSIONS--Influences acting in early life may be important determinants of blood pressure in the first decade. The relation between birth weight and blood pressure may reflect the rate of weight gain in infancy. The reasons for the relation with birth rank and maternal age are unknown; if confirmed they imply that delayed motherhood and smaller family size may be associated with higher blood pressure in offspring.     

Sodium restriction and blood pressure in hypertensive type II diabetics: randomised blind controlled and crossover studies of moderate sodium restriction and sodium supplementation.

OBJECTIVE--To determine the effect of moderate dietary sodium restriction on the hypertension of non-insulin-dependent (type II) diabetes. DESIGN--Randomised parallel controlled study of moderate sodium restriction for three months compared with usual diabetic diet, followed by randomised double blind crossover trial of sustained release preparation of sodium for one month versus placebo for one month in patients continuing with sodium restriction. SETTING--Patients attending diabetic outpatient clinic of city hospital. PATIENTS--Thirty four patients with established type II diabetes complicated by mild hypertension (systolic blood pressure greater than 160 mm Hg or diastolic pressure greater than 95 mm Hg on three consecutive occasions). Patients already taking antihypertensive agents (but not diuretics) not barred from study provided that criteria for mild hypertension still met. Conditions precluding patients from study were diabetic or hypertensive nephropathy, cardiac failure, and pregnancy. INTERVENTIONS--After run in phase with recordings at seven weeks, three weeks, and time zero patients were allocated at random to receive moderate dietary sodium restriction for three months (n = 17) or to continue with usual diabetic diet. Subsequently nine patients in sodium restriction group continued with regimen for a further two months, during which they completed a randomised double blind crossover trial of sustained release preparation of sodium (Slow Sodium 80 mmol daily) for one month versus matching placebo for one month. END POINT--Reduction in blood pressure in type II diabetics with mild hypertension. MEASUREMENTS AND MAIN RESULTS--Supine and erect blood pressure, body weight, and 24 hour urinary sodium and potassium excretion measured monthly during parallel group and double blind crossover studies. After parallel group study sodium restriction group showed significant reduction in systolic blood pressure (supine 19.2 mm Hg, erect 21.4 mm Hg; p less than 0.001) and mean daily urinary sodium excretion (mean reduction 60 mmol/24 h). There were no appreciable changes in weight, diabetic control, or diastolic pressure. No significant changes occurred in controls. In double blind crossover study mean supine systolic blood pressure rose significantly (p less than 0.005) during sodium supplementation (to 171 mm Hg) compared with value after three months of sodium restriction alone (159.9 mm Hg) and after one month of placebo (161.8 mm Hg). CONCLUSIONS--Moderate dietary restriction of sodium has a definite hypotensive effect, which may be useful in mild hypertension of type II diabetes.     

Value of low dose combination treatment with blood pressure lowering drugs: analysis of 354 randomised trials

Objective To determine the average reduction in blood pressure, prevalence of adverse effects, and reduction in risk of stroke and ischaemic heart disease events produced by the five main categories of blood pressure lowering drugs according to dose, singly and in combination.Design Meta-analysis of 354 randomised double blind placebo controlled trials of thiazides, β blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor antagonists, and calcium channel blockers in fixed dose.Subjects 40 000 treated patients and 16 000 patients given placebo.Main outcome measures Placebo adjusted reductions in systolic and diastolic blood pressure and prevalence of adverse effects, according to dose expressed as a multiple of the standard (recommended) doses of the drugs.Results All five categories of drug produced similar reductions in blood pressure. The average reduction was 9.1 mm Hg systolic and 5.5 mm Hg diastolic at standard dose and 7.1 mm Hg systolic and 4.4 mm Hg diastolic (20% lower) at half standard dose. The drugs reduced blood pressure from all pretreatment levels, more so from higher levels; for a 10 mm Hg higher blood pressure the reduction was 1.0 mm Hg systolic and 1.1 mm Hg diastolic greater. The blood pressure lowering effects of different categories of drugs were additive. Symptoms attributable to thiazides, β blockers, and calcium channel blockers were strongly dose related; symptoms caused by ACE inhibitors (mainly cough) were not dose related. Angiotensin II receptor antagonists caused no excess of symptoms. The prevalence of symptoms with two drugs in combination was less than additive. Adverse metabolic effects (such as changes in cholesterol or potassium) were negligible at half standard dose.Conclusions Combination low dose drug treatment increases efficacy and reduces adverse effects. From the average blood pressure in people who have strokes (150/90 mm Hg) three drugs at half standard dose are estimated to lower blood pressure by 20 mm Hg systolic and 11 mm Hg diastolic and thereby reduce the risk of stroke by 63% and ischaemic heart disease events by 46% at age 60-69.     

Controlled trial of biofeedback-aided behavioural methods in reducing mild hypertension.

Employees of a large industry were screened for the presence of coronary risk factors. A total of 204 employees, aged 35-64 years, with two or more such factors (serum cholesterol concentration greater than or equal to 6.3 mmol/l (243.6 mg/100 ml), blood pressure greater than or equal to 140/90 mm Hg, and current cigarette consumption greater than or equal to 10 cigarettes a day) were randomly allocated to a biofeedback group receiving training in relaxation and management of stress or a control group. Both groups received simple health education literature. After eight weeks of training, and again eight months later, the biofeedback group showed a significantly greater fall in systolic and diastolic blood pressures than the control group (p less than 0.001). Plasma renin activity and plasma aldosterone concentration were measured in a subsample at entry to the study and again at eight weeks and eight months; both showed a greater reduction in the biofeedback compared with the control group at eight weeks'' follow-up. The greater reduction in blood pressure in the subjects in the biofeedback group compared with the control group (11.0 mm Hg systolic and 8.8 mm Hg diastolic), persisting eight months after the training, suggests that relaxation-based behavioural methods might be offered as a first-time treatment to patients with mild hypertension.     

Effect on intra-arterial blood pressure of slow release metoprolol combined with placebo or chlorthalidone.

Thirty patients with essential hypertension participated in a double blind crossover trial in which they were randomly allocated to treatment with either once daily slow release metoprolol (200 mg) with placebo or once daily slow release metoprolol (200 mg) with chlorthalidone (25 mg). Ambulatory intra-arterial blood pressure was recorded continuously for 24-48 hours before treatment and two months after each change in regimen. The response of blood pressure and pulse rate to a standard exercise protocol that included supine rest and tilt, isometric, and dynamic bicycle exercise was measured during the same recording periods. Both treatments appreciably reduced blood pressure and pulse rate; mean daytime intra-arterial blood pressure was reduced from 174/95 mm Hg to 158/85 mm Hg by metoprolol plus placebo and to 143/78 mm Hg by metoprolol plus chlorthalidone. This reduction with the combined treatment was significantly greater than with metoprolol and placebo (p systolic = 0.001, p diastolic = 0.004). Mean night time pressures were reduced from 148/78 mm Hg to 139/75 mm Hg by metoprolol plus placebo and to 116/61 mm Hg by metoprolol plus chlorthalidone. Again the reduction in blood pressure was significantly greater with combined treatment (p less than 0.001) than with metoprolol plus placebo. Once daily slow release metoprolol is effective in controlling blood pressure, but this effect is greatly enhanced by the addition of a diuretic.     

Systolic and diastolic blood pressures as predictors of coronary heart disease mortality in the Whitehall study.

Systolic and diastolic blood pressures were compared as predictors of death due to coronary heart disease using data on the 10 year mortality outcome from the 18 403 male civil servants, aged 40-64, in the Whitehall study. There were 727 deaths due to coronary heart disease. At entry to the study the systolic pressure in these men was significantly higher than the diastolic pressure, and a standardised index of relative risk for death from coronary heart disease was greater for systolic blood pressure. After adjustment for age the top quintile of systolic pressure (greater than 151 mm Hg) identified 5% more men at risk of death from coronary heart disease than for the top diastolic quintile (greater than 95 mm Hg). The findings suggested that clinicians should pay more attention to systolic levels as a criterion for making diagnostic and therapeutic decisions.     

Factors related to first dose hypotensive effect of captopril: prediction and treatment.

The blood pressure response to the first dose of captopril (6.25 mg, 12.5 mg, or 25 mg) was measured in 65 treated, severely hypertensive patients. Mean supine blood pressure was 187/108 mm Hg immediately before captopril was given. Twenty one patients experienced a fall in supine systolic pressure greater than 50 mm Hg, including five whose pressure fell more than 100 mm Hg and two whose pressure fell more than 150 mm Hg. Six patients developed symptoms of acute hypotension, including dizziness, stupor, dysphasia, and hemiparesis. Percentage reductions in blood pressure were greatest in those with secondary hypertension (p less than 0.05), high pretreatment blood pressure (p less than 0.05), and high concentrations of plasma renin and angiotensin II (p less than 0.01). No significant correlation was found between fall in blood pressure and serum sodium concentration, age, renal function, and the dose of captopril given. A severe first dose effect cannot be consistently predicted in individual patients who have received other antihypertensive drugs for severe hypertension. Such patients should have close medical supervision for at least three hours after the first dose of captopril.     

Three year follow up of patients with raised blood pressure identified at health checks in general practice.

OBJECTIVE--To assess the extent of three year follow up of blood pressure, weight, and smoking habit in patients with raised blood pressure identified at health checks. DESIGN--Retrospective audit of medical and nursing records. SETTING--Three general practices in Oxfordshire. PATIENTS--386 of 448 patients with raised blood pressure (diastolic greater than or equal to 90 or systolic greater than or equal to 160 mm Hg) identified from 2935 patients aged 35-64 attending health checks in 1982-4. MEASUREMENTS and MAIN RESULTS--All records of blood pressure, weight, and smoking habit in the medical record were abstracted for three years after the initial health check. All 42 patients with an initial diastolic blood pressure greater than or equal to 105 mm Hg and 316 of 344 patients with an initial pressure of 90-104 mm Hg had at least one further measurement of their blood pressure. Follow up of smoking habit and of weight was less complete with only half of the 100 smokers and 67 of the 87 obese patients (body mass index greater than or equal to 30) having any documented follow up of these risk factors. Annual follow up in the second and third years occurred in 228/297 (76.8%) and 232/320 (72.5%) in patients with blood pressure greater than 95 mm Hg at the beginning of each year. For patients who smoked annual follow up in these years occurred in fewer than a third and for those who were obese in just over half. On the assumption that those not followed up had not changed, at the end of three years the proportion of patients with diastolic blood pressure greater than or equal to 100 mm Hg had fallen from 61 patients (15.8%) to 31 (8.1%); the proportion of smokers had fallen from 103 (26.7%) to 94 (24.4%); and the proportion of obese patients had fallen from 87 (22.5%) to 79 (20.5%). CONCLUSIONS--These changes were modest and in the absence of a control group cannot be attributed necessarily to health checks. Although the standard of follow up was better than in previously reported studies of the management of hypertension, the results emphasise the need to develop formal protocols for dietary and antismoking interventions and to evaluate formally the effectiveness (and cost effectiveness) of health checks.     

Fetal and placental size and risk of hypertension in adult life.

OBJECTIVE--To study the effect of intrauterine growth and maternal physique on blood pressure in adult life. DESIGN--A follow up study of infants born 50 years previously whose measurements at birth were recorded in detail. SETTING--Preston, Lancashire. SUBJECTS--449 Men and women born in hospital in Preston during 1935-43 and still living in Lancashire. MAIN OUTCOME MEASURES--Placental weight, birth weight, and blood pressure at age 46 to 54 years. RESULTS--In both sexes systolic and diastolic pressures were strongly related to placental weight and birth weight. Mean systolic pressure rose by 15 mm Hg as placental weight increased from less than or equal to 1 lb (0.45 kg) to greater than 1.5 lb and fell by 11 mm Hg as birth weight increased from less than or equal to 5.5 lb to greater than 7.5 lb. These relations were independent so that the highest blood pressures occurred in people who had been small babies with large placentas. Higher body mass index and alcohol consumption were also associated with higher blood pressure, but the relations of placental weight and birth weight to blood pressure and hypertension were independent of these influences. CONCLUSIONS--These findings show for the first time that the intrauterine environment has an important effect on blood pressure and hypertension in adults. The highest blood pressures occurred in men and women who had been small babies with large placentas. Such discordance between placental and fetal size may lead to circulatory adaptation in the fetus, altered arterial structure in the child, and hypertension in the adult. Prevention of hypertension may depend on improving the nutrition and health of mothers.     

Long-term follow-up of a hypertension screening program.

Of 185 people found to be hypertensive in a shopping centre screening program who went to their physician and had medication prescribed, then were contacted 18 months later, 33 had discontinued the medication at their physician''s request. But of 152 who were to continue taking medication 139 (91.4%) had complied. Blood pressure had decreased to less than 160 mm Hg systolic or less than 95 mm Hg diastolic, or both, in 65.1% of the 152; was 160 to 169 mm Hg systolic or 95 to 99 mm Hg diastolic, or both, in 13.8%; was mildly or moderately decreased but still above 169 mm Hg systolic or 99 mmHg diastolic, or both, in 8.6%; and was higher than before the onset of treatment in 3.9%. Adequacy of blood pressure control was not related to age, sex, initial blood pressure values, awareness before the screening of having hypertension, or treatment for hypertension before the screening. Diuretics had been prescribed for 93.5% of the 139 patients, most often as single-pill combinations with other antihypertensive agents.     

Pulsus paradoxus in asthmatic children.

Pulsus paradoxus is a useful physical sign in the assessment of the severity of asthma in adults. Whether this is also true for asthmatic children was determined by measuring respiratory fluctuations in systolic blood pressure during attacks of asthma in 24 children. A decrease in systolic pressure during inspiration exceeding 15 mm Hg was found only when the 1-second forced expiratory volume was less tha 60 percent of the predicted value. There was a highly significant (P smaller than 0.001) correlation between the degree of pulsus paradoxus and the severity of airway obstruction. In nonasthmatic children the systolic pressure was found to fluctuate by as much as 7 mm Hg during the respiratory cycle. It is concluded that, as in adults, the presence of pulsus paradoxus (larger than or equal to 15 mm Hg) in children indicates that their asthma is very severe.     

Community care compared with hospital outpatient care for hypertensive patients.

Three hundred and seventy-six patients with treated diastolic blood pressures of less than 105 mm Hg and no history of accelerated hypertension or renal failure were selected from among those attending the Hammersmith Hospital hypertension clinic. Their average lying treated blood pressure was 146 mm Hg systolic and 90 mm Hg diastolic and average age 56 years; 18% were black, 6% Asian, and 76% white. The patients were mostly having multiple treatment, 90% receiving a diuretic, 35% methyldopa, 33% propranolol, 18% atenolol, 9% hydrallazine, and 7% bethanidine. They were randomly allocated to either two years of further hospital outpatient care or referred back to their general practitioners. During the two years 19 (10%) of the 187 patients followed up in hospital defaulted and three had their treatment discontinued. Twelve (6%) of the 189 followed up by their general practitioners defaulted from follow-up and nine had their treatment discontinued. At the end of the trial the average lying blood pressure was 148 mm Hg systolic and 88 mm Hg diastolic in the hospital group and 149 mm Hg systolic and 90 mm Hg diastolic in the general practice group. The change in blood pressure was calculated for each individual and showed an average fall of 1.6 mm Hg in standing diastolic pressure in the hospital group and a rise of 1.4 mm Hg in the general practice group (p less than 0.05). The 90% confidence limits for a difference in standing diastolic pressure between the groups were 1 and 5 mm Hg with the pressure lower in the hospital group. General practice care was not quite as effective in controlling blood pressure as continued specialist supervision over two years in this selected group of treated outpatients with mild or moderate hypertension, but these results show that the discharge back to general practitioners of patients who are well controlled after hospital treatment is a sensible policy.     

Endpiece: It works in every country

ObjectivesTo determine whether any vital signs can be used to quickly identify brain lesions in patients with impaired consciousness. DesignCross sectional observational study.SettingEmergency department of an urban hospital, Japan.Participants529 consecutive patients (mean age 65 years) presenting with impaired consciousness (score <15 on the Glasgow coma scale) during 2000.Results312 (59%) had a brain lesion which accounted for the impaired consciousness. The area under the receiver operating curve for systolic blood pressure was 0.90 (SE 0.01), indicating significantly higher accuracy (P<0.01) in the identification of a brain lesion than using diastolic pressure 0.82 (0.02) or pulse rate 0.63 (0.03). Likelihood ratios for systolic blood pressure lower than 90 mm Hg were less than 0.04, and those for systolic pressure higher than 170 mm Hg were greater than 6.09.ConclusionsSystolic blood pressure is useful for diagnosing brain lesions in patients with impaired consciousness.

What is already known on this topic

Brain imaging and neurological examination of patients with impaired consciousness are often a waste of time and resources and can delay correct diagnosis

What this paper adds

Systolic blood pressure distinguishes patients with impaired consciousness who are at high risk from those who are at low risk of an organic brain lesionGeneral use of systolic blood pressure in the diagnosis of impaired consciousness may have clinical and economic benefits     

Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations. Intersalt Cooperative Research Group.

OBJECTIVES--To assess further the relation in Intersalt of 24 hour urinary sodium to blood pressure of individuals and populations, and the difference in blood pressure from young adulthood into middle age. DESIGN--Standardised cross sectional study within and across populations. SETTING--52 population samples in 32 countries. SUBJECTS--10,074 men and women aged 20-59. MAIN OUTCOME MEASURES--Association of sodium and blood pressure from within population and cross population multiple linear regression analyses with multivariate correction for regression dilution bias. Relation of sample median daily urinary sodium excretion to difference in blood pressure with age. RESULTS--In within population analyses (n = 10,074), individual 24 hour urinary sodium excretion higher by 100 mmol (for example, 170 v 70 mmol) was associated with systolic/diastolic blood pressure higher on average by 3/0 to 6/3 mm Hg (with and without body mass in analyses). Associations were larger at ages 40-59. In cross population analyses (n = 52), sample median 24 hour sodium excretion higher by 100 mmol was associated with median systolic/diastolic pressure higher on average by 5-7/2-4 mm Hg, and estimated mean difference in systolic/diastolic pressure at age 55 compared with age 25 greater by 10-11/6 mm Hg. CONCLUSIONS--The strong, positive association of urinary sodium with systolic pressure of individuals concurs with Intersalt cross population findings and results of other studies. Higher urinary sodium is also associated with substantially greater differences in blood pressure in middle age compared with young adulthood. These results support recommendations for reduction of high salt intake in populations for prevention and control of adverse blood pressure levels.     

Sodium and potassium intake and blood pressure change in childhood.

OBJECTIVE--To assess the association between sodium and potassium intake and the rise in blood pressure in childhood. DESIGN--Longitudinal study of a cohort of children with annual measurements during an average follow up period of seven years. SETTING--Epidemiological survey of the population of a suburban town in western Netherlands. SUBJECTS--Cohort of 233 children aged 5-17 drawn at random from participants in the population survey. MAIN OUTCOME MEASURES--At least six annual timed overnight urine samples were obtained. The mean 24 hour sodium and potassium excretion during the follow up period was estimated for each participant and the sodium to potassium ratio calculated. Individual slopes of blood pressure over time were calculated by linear regression analysis. RESULTS--No significant association was observed between sodium excretion and the change in blood pressure over time. The mean systolic blood pressure slopes, however, were lower when potassium intake was higher (coefficient of linear regression -0.045 mm Hg/year/mmol; 95% confidence interval -0.069 to -0.020), and the change in systolic pressure was greater when the urinary sodium to potassium ratio was higher (0.356 mm Hg/year/unit; 95% confidence interval 0.069 to 0.642). In relation to potassium this was interpreted as a rise in blood pressure that was on average 1.0 mm Hg (95% confidence interval -1.65 to -0.35) lower in children in the upper part of the distribution of intake compared with those in the lower part. The mean yearly rise in systolic blood pressure for the group as a whole was 1.95 mm Hg. Urinary electrolyte excretion was not associated with diastolic blood pressure. CONCLUSION--Dietary potassium and the dietary sodium to potassium ratio are related to the rise in blood pressure in childhood and may be important in the early pathogenesis of primary hypertension.     

Raised arterial pressure in parents of proteinuric insulin dependent diabetics.

Arterial pressure is raised early in the subset of insulin dependent diabetics at risk of later development of progressive renal failure, suggesting that liability to arterial hypertension may play a part in the aetiology of diabetic kidney disease. Evidence for a genetic basis was therefore sought by measuring the blood pressures of the 26 surviving parents of 17 insulin dependent diabetic patients with proteinuria and comparing them with those of the parents of 17 matched insulin dependent diabetic patients without proteinuria selected from the same cohort. Systolic and diastolic pressures were significantly higher in parents of the proteinuric (mean (SD) 161 (27)/94 (14) mm Hg) than in parents of the non-proteinuric patients (146 (21)/86 (11) mm Hg). The difference between the sample mean blood pressures was 15 mm Hg (95% confidence interval 3.3 to 26.7 mm Hg) for systolic pressure and 8 mm Hg (95% confidence interval 0.8 to 15.2 mm Hg) for diastolic pressure. These differences were independent of age, sex, and adiposity. There was a significant correlation between the mean arterial pressures in the proteinuric patients and the higher mean blood pressure in their parents. High blood pressure in non-diabetic parents may be a marker of susceptibility to clinical nephropathy in their insulin dependent diabetic offspring.     

Low blood pressure and dementia in elderly people: the Kungsholmen project.

OBJECTIVE--To examine the relation between blood pressure and dementia in elderly people. DESIGN--Cross sectional, population based study. SETTING: Kungsholmen district of Stockholm, Sweden. SUBJECTS-- 1642 subjects aged 75-101 years. MAIN OUTCOME MEASURES--Prevalence and adjusted odds ratio of dementia by blood pressure. RESULTS--People with systolic pressure < or = 140 mm Hg were more often diagnosed as demented than those with systolic pressure >140 mm Hg: odds ratios (95% confidence interval) adjusted for age, sex, and education were 2.98 (2.17 to 4.08) for all dementias, 2.91 (1.93 to 4.38) for Alzheimer''s disease, 2.00 (1.09 to 3.65) for vascular dementia, and 5.07 (2.65 to 9.70) for other dementias. Similar results were seen in subjects with diastolic pressure < or = 75 mm Hg compared with those with higher diastolic pressure. When severity and duration of dementia were taken into account, only moderate and severe dementia were found to be significantly related to relatively low blood pressure, and the association was stronger in subjects with longer disease duration. Use of hypotensive drugs and comorbidity with cardiovascular disease did not modify the results for all dementias, Alzheimer''s disease, and other dementias but slightly reduced the association between vascular dementia and diastolic blood pressure. CONCLUSIONS--Both systolic and diastolic blood pressure were inversely related to prevalence of dementia in elderly people. We think that relatively low blood pressure is probably a complication of the dementia process, particularly Alzheimer''s disease, although it is possible that low blood pressure may predispose a subpopulation to developing dementia.     

Comparison of direct and indirect blood pressure measurement in anesthetized dogs.

This study was conducted to determine whether blood pressures and pulse rate could be determined accurately by indirect measurements from the front and hind legs of 15- to 40-kg dogs anesthetized with isoflurane. Indirect measurements from each animal were compared to direct measurements obtained from a catheter placed into the abdominal aorta via the femoral artery at four ranges of systolic pressure. When systolic pressure was above 80 mm Hg, indirect measurements were either the same as direct measurements or slightly lower. However, when systolic pressures were below 80 mm Hg, indirect systolic pressure measurements were 6 to 15% higher than direct measurements. Larger differences in diastolic pressures were found, which resulted in differences in mean pressure. The most accurate measurements were found when the cuff width-to-limb circumference ratio was between 0.4 and 0.6 and when systolic pressure was between 80 and 100 mm Hg.     

Blood pressure control by home monitoring: meta-analysis of randomised trials

Objective To determine the effect of home blood pressure monitoring on blood pressure levels and proportion of people with essential hypertension achieving targets.Design Meta-analysis of 18 randomised controlled trials.Participants 1359 people with essential hypertension allocated to home blood pressure monitoring and 1355 allocated to the “control” group seen in the healthcare system for 2-36 months.Main outcome measures Differences in systolic (13 studies), diastolic (16 studies), or mean (3 studies) blood pressures, and proportion of patients achieving targets (6 studies), between intervention and control groups.Results Systolic blood pressure was lower in people with hypertension who had home blood pressure monitoring than in those who had standard blood pressure monitoring in the healthcare system (standardised mean difference 4.2 (95% confidence interval 1.5 to 6.9) mm Hg), diastolic blood pressure was lower by 2.4 (1.2 to 3.5) mm Hg, and mean blood pressure was lower by 4.4 (2.0 to 6.8) mm Hg. The relative risk of blood pressure above predetermined targets was lower in people with home blood pressure monitoring (risk ratio 0.90, 0.80 to 1.00). When publication bias was allowed for, the differences were attenuated: 2.2 (-0.9 to 5.3) mm Hg for systolic blood pressure and 1.9 (0.6 to 3.2) mm Hg for diastolic blood pressure.Conclusions Blood pressure control in people with hypertension (assessed in the clinic) and the proportion achieving targets are increased when home blood pressure monitoring is used rather than standard blood pressure monitoring in the healthcare system. The reasons for this are not clear. The difference in blood pressure control between the two methods is small but likely to contribute to an important reduction in vascular complications in the hypertensive population.     

Control of blood pressure and risk of first acute myocardial infarction: Skaraborg hypertension project.

OBJECTIVE--To analyse the relation between treated blood pressure and concomitant risk factor and morbidity from acute myocardial infarction. DESIGN--Prospective longitudinal study. Treated blood pressures and other variables were used to predict acute myocardial infarction. SETTING--Primary health care in Skaraborg, Sweden. SUBJECTS--1121 men and 1453 women aged 40-69 years at registration at outpatient clinics, 1977-81, with no evidence of previous myocardial infarction were followed up for an average of 7.4 years. Subjects were undergoing treatment with drugs to lower blood pressure or had blood pressure that exceeded the systolic or diastolic limits, or both, for diagnosis (> 170/> 105 mm Hg (patients aged 40-60 years) and > 180/> 110 mm Hg (older than 60 years)) on three different occasions, or both. MAIN OUTCOME MEASURES--First validated event of fatal or non-fatal acute myocardial infarction. RESULTS--In men but not in women there was a negative relation between treated diastolic blood pressure and risk of acute myocardial infarction. Left ventricular hypertrophy and smoking were contributory risk factors in both sexes, as was serum cholesterol concentration in men. In men with normal electrocardiograms (n = 345) risk increased with increasing diastolic blood pressure (P = 0.047), whereas the opposite was found in men with electrocardiograms suggesting ischaemia or hypertrophy, or both (n = 499, P = 0.009). In those with a reading of 95-99 mm Hg the relative risk was 0.30 (P = 0.034); at > or = 100 mm Hg it was 0.37 (P = 0.027). No similar relations were seen in women or for systolic blood pressure. CONCLUSION--It may be hazardous to lower diastolic blood pressure below 95 mm Hg in hypertensive men with possible ischaemia or hypertrophy, or both. Electrocardiographic findings should be considered when treatment goals are decided for men with hypertension.