Comparison of randomization techniques for clinical trials with data from the HOMERUS-trial.

BACKGROUND: Several methods of randomization are available to create comparable intervention groups in a study. In the HOMERUS-trial, we compared the minimization procedure with a stratified and a non-stratified method of randomization in order to test which one is most appropriate for use in clinical hypertension trials. A second objective of this article was to describe the baseline characteristics of the HOMERUS-trial. METHODS: The HOMERUS population consisted of 459 mild-to-moderate hypertensive subjects (54% males) with a mean age of 55 years. These patients were prospectively randomized with the minimization method to either the office pressure (OP) group, where antihypertensive treatment was based on office blood pressure (BP) values, or to the self-pressure (SP) group, where treatment was based on self-measured BP values. Minimization was compared with two other randomization methods, which were performed post-hoc: (i) non-stratified randomization with four permuted blocks, and (ii) stratified randomization with four permuted blocks and 16 strata. In addition, several factors that could influence outcome were investigated for their effect on BP by 24-h ambulatory blood pressure monitoring (ABPM). RESULTS: Minimization and stratified randomization did not lead to significant differences in 24-h ABPM values between the two treatment groups. Non-stratified randomization resulted in a significant difference in 24-h diastolic ABPM between the groups. Factors that caused significant differences in 24-h ABPM values were: region, centre of patient recruitment, age, gender, microalbuminuria, left ventricular hypertrophy and obesity. CONCLUSION: Minimization and stratified randomization are appropriate methods for use in clinical trials. Many outcome factors should be taken into account for their potential influence on BP levels. Recommendation. Due to the large number of potential outcome factors that can influence BP levels, minimization should be the preferred method for use in clinical hypertension trials, as it has the potential to randomize more outcome factors than stratified randomization.

Asymptomatic peripheral arterial occlusive disease predicted cardiovascular morbidity and mortality in a 7-year follow-up study.

OBJECTIVE: Asymptomatic peripheral arterial occlusive disease (PAOD) is a common atherosclerotic disorder among the elderly population. Scarce data are available on the risk of nonfatal and fatal cardiovascular diseases in these subjects. We investigated cardiovascular morbidity and mortality of asymptomatic PAOD subjects. STUDY DESIGN AND SETTING: A sample of 3649 subjects (40-78 years of age) was selected in collaboration with 18 general practice centers and followed up after the initial screening (mean follow-up time 7.2 years). Asymptomatic PAOD was determined by means of the ankle-brachial pressure index (ABPI). Main outcome measures were nonfatal cardiovascular events and mortality. RESULTS: Cox proportional hazard models showed that asymptomatic PAOD was significantly associated with cardiovascular morbidity (hazard ratio [HR] 1.6, 95% confidence interval [CI] 1.3-2.1), total mortality (HR 1.4, 95% CI 1.1-1.8), and cardiovascular mortality (HR 1.5, 95% CI 1.1-2.1). CONCLUSION: Asymptomatic PAOD is a significant predictor of cardiovascular morbidity and mortality. In high-risk subjects, measurement of the ABPI provides valuable information on future cardiovascular events.

Changing world, changing doctors, changing education!

Future developments in the community will underline the need to provide a community-oriented health care system in which public health doctors collaborate with general practitioners, as the hospital-based health care system that currently exists in many countries will not be able to solve the problems of health care in the future. Increasing populations, increasing mobility all over the world, spread of new diseases (aids/hiv and ebola virus for example) will have great impact on our societies and the expectations of the societies and patients of their doctors. Most societies in which our young doctors will serve, expect their adults to live on healthily into their 80th. That means that the society of the future will be a double aging society (more older people who are older than before) with all concomitant burdens of degenerative chronic diseases. How should we handle the problems in 2025 when our capacities stay restricted to what we once learned in 2002? For this purpose the medical faculties have to change their curricula. The medical faculties will have to educate different kind of doctors, different from the doctors they have educated for many decades. These doctors must collaborate with other health care workers in primary health care teams. Collaboration in these teams requires mutual trust, win-win situations and agreement on the principles of health promotion programs. Only by collaboration between public health care and individual, personal health care it will be possible to achieve unity for health for all people. In the future both public health doctors and general practitioners need each other's complementary support and since they share the same area of interest, they need to work together.

Incidence of and risk factors for asymptomatic peripheral arterial occlusive disease: a longitudinal study.

The current study describes the age- and sex-specific incidence rates and risk factors for asymptomatic and symptomatic peripheral arterial occlusive disease (PAOD) among 2,327 subjects and the incidence of intermittent claudication in asymptomatic PAOD subjects. The study population was selected from 18 general practice centers in the Netherlands. PAOD was assessed with the ankle-brachial blood pressure index, and intermittent claudication was assessed with a modified version of the Rose questionnaire. After 7.2 years, the overall incidence rate for asymptomatic PAOD, using the person-years method, was 9.9 (95% confidence interval (CI): 7.3, 18.8) per 1,000 person-years at risk. The rate was 7.8 (95% CI: 4.9, 20.3) for men and 12.4 (95% CI: 7.7, 24.8) for women. For symptomatic PAOD, the incidence rate was 1.0 (95% CI: 0.7, 7.5) overall, 0.4 (95% CI: 0.3, 10.0) for men, and 1.8 (95% CI: 1.0, 10.3) for women. Multivariate analyses showed that increasing age, smoking, hypertension, and diabetes mellitus were the most important risk factors. The overall incidence rate for intermittent claudication among PAOD subjects who were asymptomatic at baseline was 90.5 per 1,000 person-years at risk (95% CI: 36.4, 378.3). The incidence of asymptomatic PAOD was higher than the incidence of symptomatic PAOD, with women developing PAOD more often than men. In the development of preventive strategies, modification of atherosclerotic risk factors, such as smoking, hypertension, and diabetes, should be the main goals.

Management of acute uncomplicated urinary tract infections in general practice in the south of The Netherlands.

There is debate about the ideal diagnostic procedure for urinary tract infections (UTIs) in general practice. The aim of this study was to evaluate nitrite and leucocyte esterase strip test procedures in general practice patients, and to relate the results to the decision of the general practitioner to prescribe antibiotic therapy. A total of 292 female patients from eight general practices in the Maastricht area, who were aged 12 years or over with complaints suggesting UTI, were included in the study. All eight practices tested fresh urine samples using the nitrite strip test, and seven also used the leucocyte esterase strip test. The positive predictive value of the nitrite test was greater than the leucocyte test. Antibiotic therapy was nearly always prescribed when either or both of these tests were positive. Bacterial culture was positive in 159 (59%) cases, although treatment was started in 70 (27%) cases where there was an absence of significant bacteruria. It was found that the choice of agent used to treat the patient was related to the antibiotic susceptibility of the uropathogens that were isolated.

Primary prevention of arterial thromboembolism in non-rheumatic atrial fibrillation in primary care: randomised controlled trial comparing two intensities of coumarin with aspirin.

OBJECTIVE: To investigate the effectiveness of aspirin and coumarin in preventing thromboembolism in patients with non-rheumatic atrial fibrillation in general practice. DESIGN: Randomised controlled trial. PARTICIPANTS: 729 patients aged >/=60 years with atrial fibrillation, recruited in general practice, who had no established indication for coumarin. Mean age was 75 years and mean follow up 2. 7 years. SETTING: Primary care in the Netherlands. INTERVENTIONS: Patients eligible for standard intensity coumarin (international normalised ratio 2.5-3.5) were randomly assigned to standard anticoagulation, very low intensity coumarin (international normalised ratio 1.1-1.6), or aspirin (150 mg/day) (stratum 1). Patients ineligible for standard anticoagulation were randomly assigned to low anticoagulation or aspirin (stratum 2). MAIN OUTCOME MEASURES: Stroke, systemic embolism, major haemorrhage, and vascular death. RESULTS: 108 primary events occurred (annual event rate 5.5%), including 13 major haemorrhages (0.7% a year). The hazard ratio was 0.91 (0.61 to 1.36) for low anticoagulation versus aspirin and 0.78 (0.34 to 1.81) for standard anticoagulation versus aspirin. Non-vascular death was less common in the low anticoagulation group than in the aspirin group (0.41, 0.20 to 0.82). There was no significant difference between the treatment groups in bleeding incidence. High systolic and low diastolic blood pressure and age were independent prognostic factors. CONCLUSION: In a general practice population (without established indications for coumarin) neither low nor standard intensity anticoagulation is better than aspirin in preventing primary outcome events. Aspirin may therefore be the first choice in patients with atrial fibrillation in general practice.

Primary prevention of arterial thromboembolism in nonrheumatic atrial fibrillation: the PATAF trial study design.

Patients with nonrheumatic atrial fibrillation (NRAF) have a higher risk of thromboembolism than patients in sinus rhythm. Several trials have been conducted to establish the best preventive regimen in patients with NRAF, but not in the primary-care setting. The Primary Prevention of Arterial Thromboembolism in Nonrheumatic Atrial Fibrillation (PATAF) study, a primary-care-based trial, was set up to compare the preventive efficacy of low-intensity anticoagulation (AC), target range International Normalized Ratio (INR) 1.1 < INR < 1.6 and regular-intensity AC (2.5 < INR < 3.5) therapies with that of aspirin 150 mg/d for the occurrence of thromboembolism in NRAF patients. Patients eligible for regular-intensity AC were randomly assigned to aspirin at 150 mg/d, low-intensity AC, or regular AC in group I. In cases of noneligibility for regular AC, the trial randomized patients between aspirin and low-intensity AC (assigned to group II). Primary outcome events were stroke (including intracranial hemorrhage), systemic embolism, major hemorrhage, or vascular death. Analysis of the data was based on Cox regression to compute the hazard ratio (HR) with a 95% confidence interval, using the likelihood ratio test. The trial randomized 729 patients. Patient enrollment and follow-up has been stopped, and the final analysis is now complete. We shall publish the main results as soon as possible.

Development of blood pressure and the incidence of hypertension in men and women over an 18-year period: results of the Nijmegen Cohort Study.

The objective of this study was to determine the factors that influence diastolic blood pressure (DBP) and the incidence of hypertension. In 1977, DBP and cardiovascular risk factors were measured in 7092 men and women. In 1995, 2335 subjects participated at a second screening. Those patients already under hypertension treatment in 1977 were excluded. The DBP tracking was studied in subjects not under hypertension treatment during the study. Hypertension was defined on two ways in the analysis: under current hypertension treatment or a DBP > 95 mmHg measured at rescreening in 1995. Forty-seven percent of the subjects with a DBP < 75 mmHg in 1977 remained in the same category of DBP in 1995, and 7% had become hypertensive. Of the 75-84 mmHg group in 1977, 40% stayed in the same category in 1995 and 15% became hypertensive. Of the 85-94 mmHg category, 30% stayed in the same category and 30% became hypertensive in 1995. Of the highest category in 1977 (> 95 mmHg), 64% were still in that category in 1995. Baseline DBP in 1977 had the highest predictive value for future DBP. Weight gain over the years increased the risk for future hypertension: in contrast, there was no risk at a low DBP without weight gain. There is no need for regular check-ups for those patients with a low DBP who experience no weight gain. Borderline DBP (85-95 mmHg), together with weight gain, increases the risk of development of hypertension. The risk was especially high for men in the lower socioeconomic class.

Risk indicators for out-of-hospital cardiac arrest in patients with coronary artery disease.

The objective of this study was to identify risk factors for sudden cardiac arrest (SCA) in patients with coronary artery disease (CAD). A retrospective case-control study was performed consisting of a group of unselected patients who had suffered SCA and had a clinical history of CAD, and a group of unselected age- and gender-matched CAD control patients living in the region of Maastricht. Information about previous myocardial infarction (MI), left ventricular ejection fraction (LVEF), hypertension, hypercholesterolemia, diabetes mellitus, smoking, and coffee and alcohol consumption was collected. A logistic regression model was fitted to all mentioned variables including age and genders. Included were 117 SCA cases (84% men, mean age 65 years [+/-7]) and 144 control patients (83% men, mean age 63 years [+/-8]). Previous MI (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.7-9.3), hypertension (OR 2.9, 95% CI 1.5-6.1), heavy coffee consumption (>10 cups per day) (OR 55.7, 95% CI 6.4-483), and a LVEF <40% (OR 11.2, CI 4.4-28.5) were independent risk indicators for SCA in patients with CAD. Alcohol consumption (1-21 glasses per week) seemed to protect patients with CAD from SCA (OR 0.5, 95% CI 0.2-0.98). These observations suggest that changes in lifestyle factors can be of potential importance in protecting patients with CAD from dying suddenly.

The NECTAR-study: development of nutrition modules for general practice vocational training; determinants of nutrition guidance practices of GP-trainees. Nutrition Education by Computerized Training And Research.

OBJECTIVE: To identify determinants of nutrition guidance practices of general practitioner-trainees (GP-trainees), to investigate whether these determinants differ from those found by experienced general practitioners; to reveal educational directions towards the development of computer-based instruction on nutrition. DESIGN: Cross-sectional study by means of validated questionnaires. SUBJECTS: All GP-trainees in training at the eight university departments for vocational training in the Netherlands in September, 1998 (n = 985). MAIN OUTCOME MEASURES: Reliability of determinants of nutrition guidance practices was calculated by means of Crohnbach's alpha. The mechanism of action of determinants was identified by means of linear structural relationship analysis (LISREL) using a model developed for GPs. RESULTS: Crohnbach's alphas for factors ranged from 0.58-0.90. The empirical GP-trainee-data fitted with the corresponding GP-model on the mechanism of action. CONCLUSIONS: The same predisposing factors, driving forces and barriers as found with GPs were identified with GP-trainees. Comparing the GP-and GP-trainee-models, only minor differences were found in the path coefficients between factors. Lack of nutrition training and education proved to be of great influence on the extent of nutrition information given. The GP-trainee-model will be of use in developing computer-based instruction on nutrition. It is expected that GPs may also benefit from this instruction.

The prognosis of non-critical limb ischaemia: a systematic review of population-based evidence.

BACKGROUND: Peripheral arterial occlusive disease (PAOD) is the most common peripheral vascular disorder in the elderly. A clear picture of the disease's course, especially in patients with non-critical limb ischaemia (Fontaine stages I and II), is essential for the general practitioner, who plays a key role in the diagnosis and management of PAOD. AIM: To evaluate the population-based evidence on the course and prognosis of PAOD. METHODS: An exhaustive literature search yielded 16 population-based studies on the prognosis of PAOD. The methodological qualities of the studies were assessed according to eight criteria. RESULTS: Thirteen studies of high methodological quality show that data on the course, cardiovascular morbidity, and mortality of asymptomatic PAOD are scarce. Only a small group of asymptomatic patients seem to develop intermittent claudication symptoms. However, asymptomatic patients appear to have the same increased risk for cardiovascular morbidity and mortality when compared with claudicants. No data were available on prognostic factors for intermittent claudication and cardiovascular morbidity in asymptomatic patients. The course, cardiovascular morbidity, and mortality of symptomatic PAOD are better documented. A small group of claudicants experience symptom progression. Smoking, hypertension, increasing age, and diabetes are the most relevant risk factors for intermittent claudication. Claudicants are at a higher risk for developing other cardiovascular diseases, resulting in a significantly increased mortality mainly owing to coronary heart disease. Intermittent claudication and a low ankle-brachial pressure index are significant predictors of mortality. Men had intermittent claudication and symptom progression more often than women. Cardiovascular (co-)morbidity was common in both male and female PAOD patients, but male PAOD patients had a higher mortality compared with female PAOD patients. CONCLUSION: Given the current knowledge on the prognosis of PAOD in the general population, an important task for (secondary) prevention is reserved for the general practitioner. Further research is required to document the course and prognosis of asymptomatic PAOD patients.

Risk factors and cardiovascular diseases associated with asymptomatic peripheral arterial occlusive disease. The Limburg PAOD Study. Peripheral Arterial Occlusive Disease.

OBJECTIVES: To describe the risk-factor profile and cardiovascular comorbidity of asymptomatic peripheral arterial occlusive disease (PAOD). DESIGN: A cross-sectional survey. Asymptomatic PAOD was defined as an ankle-brachial pressure index < 0.95, measured on two consecutive occasions, without intermittent claudication. Logistic regression analyses were performed to investigate independent associations between age, gender, smoking status, hypertension, obesity, diabetes, hypercholesterolaemia, physical activity, a family history of cardiovascular disease, the occurrence of ischaemic heart disease and cerebrovascular disease (CeVD) and asymptomatic PAOD. SETTING: 18 general practices in the province of Limburg, the Netherlands. SUBJECTS: A total of 3650 subjects, aged 40-78 years. MAIN RESULTS: Asymptomatic PAOD was present in 8.6% (n = 314) and symptomatic disease in 3.8% (n = 138) of the participants. Age, smoking status, hypertension, and diabetes were significantly associated with asymptomatic PAOD. The ratio of asymptomatic to symptomatic PAOD was higher among the younger age groups. Male gender, hypertension and smoking status were stronger associated with symptomatic PAOD compared with asymptomatic PAOD. Asymptomatic subjects had more IHD and CeVD comorbidity compared with the healthy population. CONCLUSION: Our findings suggest that the risk-factor profile and cardiovascular comorbidity of asymptomatic subjects is comparable to claudicants. Preventive efforts could be made to diminish the influence of especially smoking, diabetes and hypertension in asymptomatic subjects.

A series of self-measurements by the patient is a reliable alternative to ambulatory blood pressure measurement.

BACKGROUND: Several studies have reported overdiagnosis and overtreatment of hypertensive patients, especially in borderline hypertensives. AIM: To find a blood pressure measurement procedure that reduces the risk of misclassification to an acceptable level. METHOD: Comparative, prospective study over seven months of primary care patients with elevated initial blood pressures. Blood pressure measurements made by general practitioners (GPs), practice nurses, and patients were compared with ambulatory blood pressure measurements. RESULTS: Ninety-nine patients completed the study. Mean differences (systolic blood pressure) between different measurement procedures and ambulatory measurement ranged from +10 mmHg (doctor) to -1 mmHg (patient), and (diastolic) from +4 mmHg (doctor) to -2 mmHg (patient). Standard deviations of mean differences ranged from 12 mmHg (doctor/systolic) to 10 mmHg (patient/systolic), and from 8 mmHg (doctor/diastolic) to 7 mmHg (patient/diastolic). CONCLUSION: Self-measurements by the patient appear to be a reliable alternative to ambulatory blood pressure measurement. In diagnosing and managing mild hypertension, we recommend the use of a valid self-measuring device.

Circumstances and causes of out-of-hospital cardiac arrest in sudden death survivors.

OBJECTIVE: To study the circumstances and medical profile of out-of-hospital sudden cardiac arrest (SCA) patients in whom resuscitation was attempted by the ambulance service, and to identify causes of SCA in survivors and factors that influence resuscitation success rate. METHODS: During a five year period (1991-95) all cases of out-of-hospital SCA between the ages of 20 and 75 years and living in the Maastricht area in the Netherlands were studied. Information was gathered about the circumstances of SCA, as well as medical history for all patients in whom resuscitation was attempted by the ambulance personnel. Causes of SCA in survivors were studied and logistic regression analysis was performed to identify factors associated with survival. RESULTS: Of 288 SCA patients in whom cardiopulmonary resuscitation (CPR) and advanced life support were applied, 47 (16%) were discharged alive from the hospital. Their mean (SD) age was 58 (11) years, 37 (79%) were men, and 24 (51%) had a history of cardiac disease. Acute myocardial infarction was diagnosed in 24 (51%) of the survivors; seven with and 17 without a history of cardiac disease. Ventricular fibrillation (VF) or ventricular tachycardia (VT) as the first documented rhythm was significantly positively associated with survival (odds ratio (OR) 5.7, 95% confidence interval (CI) 2.1 to 15.9). A time interval of less than four minutes between the moment of collapse and the start of resuscitation, and an ambulance delay time of less than eight minutes were significantly positively associated with survival (OR 3.3, 95% CI 1.3 to 8.6, and OR, 3.6, 95% CI 1.3 to 10.5, respectively). A history of cardiac disease was negatively associated with survival (OR 0.46, 95% CI 0.21 to 0.98). CONCLUSIONS: Acute myocardial infarction was the underlying mechanism of SCA in most of the survivors, especially in those without a history of cardiac disease. CPR within four minutes, an ambulance delay time less than eight minutes, and VT or VF diagnosed by the paramedics were positively associated with success.

No relevant seasonal influences on office and ambulatory blood pressure: data from a study in borderline hypertensive primary care patients.

Our objective was to study seasonal influences on office and ambulatory blood pressure. We therefore designed a prospective 7-month study of 47 borderline hypertensive patients in a primary care setting. We used no interventions. Our main outcome measures were the differences between summer and winter office and ambulatory blood pressures and 95% confidence intervals. Results showed that winter minus summer differences ranged from 0 to 3 mm Hg. Only one significant difference was found: ambulatory systolic daytime pressure was significantly higher (3 mm Hg) in winter than in summer. Our results do not confirm the data of earlier studies in hypertensives. In view of the small and clinically irrelevant winter-summer differences, it seems unnecessary to modify antihypertensive treatment of borderline hypertensives according to the season.

Out-of-hospital cardiac arrest in the 1990's: a population-based study in the Maastricht area on incidence, characteristics and survival.

OBJECTIVES: We sought to describe the incidence, characteristics and survival of out-of-hospital sudden cardiac arrest (SCA) in the Maastricht area of The Netherlands. BACKGROUND: Incidence and survival rates of out-of-hospital SCA in different communities are often based on the number of victims resuscitated by the emergency medical services. Our population-based study in the Maastricht area allows information on all victims of witnessed and unwitnessed SCA occurring outside the hospital. METHODS: Incidence, patient characteristics and survival rates were determined by prospectively collecting information on all cases of SCA occurring in the age group 20 to 75 years between January 1, 1991 and December 31, 1994. Survival rates were related to the site of the event (at home vs. outside the home) and the presence or absence of a witness and rhythm at the time of the resuscitation attempt in out-of-hospital SCA. RESULTS: Five hundred fifteen patients were included (72% men, 28% women). In 44% of men and 53% of women, SCA was most likely the first manifestation of heart disease. In patients known to have had a previous myocardial infarction (MI), the mean interval between the MI and SCA was 6.5 years, with >50% having a left ventricular ejection fraction >30%. The mean yearly incidence of SCA was 1 in 1,000 inhabitants. Of all deaths in the age groups studied, 18.5% were sudden. Nearly 80% of SCAs occurred at home. In 60% of all cases of SCA a witness was present. Cardiac resuscitation, which was attempted in 51% of all subjects, resulted overall in 32 (6%) of 515 patients being discharged alive from the hospital. Survival rates for witnessed SCA were 8% (16 of 208 subjects) at home and 18% (15 of 85 subjects) outside the home (95% confidence interval 1% to 18.8%). CONCLUSIONS: The majority of victims of SCA cannot be identified before the event. Sudden cardiac arrest usually occurs at home, and the survival of those with a witnessed SCA at home was low compared with that outside the home, indicating the necessity of optimizing out-of-hospital resuscitation, especially in the at-home situation.

Is a series of blood pressure measurements by the general practitioner or the patient a reliable alternative to ambulatory blood pressure measurement? A study in general practice with reference to short-term and long-term between-visit variability.

We studied the reproducibility of a series of blood pressure measurements by general practitioner (GP) and patient in comparison with that of ambulatory blood pressure measurement (ABPM), with reference to short-term and long-term between-visit variability using a prospective, comparative diagnostic study. The study group was 88 potentially hypertensive primary care patients (initial systolic blood pressure [SBP] between 160 and 200 mm Hg or with diastolic blood pressure [DBP] between 95 and 115 mm Hg). ABPMs were measured on 2 separate days (at a 6 month interval). Two series of measurements by the doctor (at 1 to 6 month intervals), and the patient (at a 1 week interval) were measured. Mean differences and standard deviations of mean differences (SDD) between two successive series of measurements, and between two ABPMs were computed. The Wilcoxon signed-ranks test was used to compare these standard deviations. Mean initial office-blood pressures were 161 (SBP) and 102 (DBP) mm Hg. Long-term between-visit variability (measurements by GP) was larger than short-term between-visit variability: SDDs were 16 v 11 mm Hg (SBP), and 10 v 8 mm Hg (DBP). The differences in average SBP and DBP between successive ABPMs and between successive series of office measurements by GP and home measurements by patient were not statistically significant. Mean differences between two series of measurements by GP and patient, and between two ABPMs, were 0 +/- 1 mm Hg. SDDs between successive ABPMs and series of measurements by GP and patient ranged from 8 to 11 mm Hg (SBP), and were 6 mm Hg (DBP). No statistically significant differences were found between the SDDs of the studied measurement procedures (SBP and DBP). In our study the reproducibility of ambulatory blood pressure measurement was not found to be better than that of a series of four duplicate measurements by GP or patient. Long-term (6 months interval) between-visit variability was larger than the short-term (1 week interval) between-visit variability.

How many measurements are necessary in diagnosing mild to moderate hypertension?

OBJECTIVE: The aim of this study was to investigate how many blood pressure measurements are necessary in diagnosing mild to moderate hypertension. METHODS: The subjects were 99 outpatients who were included on the basis of elevated diastolic (95 < or = DBP < or = 115 mmHg) and/or systolic (160 < or = SBP < or = 200 mmHg) blood pressure. After the initial measurement all patients underwent nine subsequent blood pressure measurements over a period of 7 months. None of the patients received anti-hypertensive drug treatment during the study. RESULTS: Between the first (initial) and second measurements, there was a significant reduction in systolic (161.0 to 152.5 mmHg) and diastolic (101.5 to 97.1 mmHg) blood pressures (P < 0.01). The differences between pairs of subsequent measurements were not statistically significant. The average of the last five assessment sessions (two readings per session) was regarded as the "conceptual average blood pressure'. Comparing the blood pressure at repeat measurement with the conceptual average blood pressure revealed misclassification in 19% of cases, even after four repeat measurements (threshold value 95 mmHg). Analysis of the subgroups (95 < or = DBP < 105 mmHg and 105 < or = DBP < or = 115 mmHg) revealed that the proportion of misclassification greatly depended on the initial value and the accepted threshold value. At a threshold value of 95 mmHg, patients with "high' initial diastolic blood pressure (105 < or = DBP < or = 115 mmHg) required only two repeat measurements (misclassification in 7% of cases after four repeat measurements). Of those with initial diastolic blood pressure values between 95 and 105 mmHg, 24% were misclassified after four repeat measurements. CONCLUSIONS: For these "borderline' diastolic values, we propose larger numbers of measurements than are recommended in international guidelines. Our advice for values in this borderline region is to be reticent in starting antihypertensive drug treatment. The presence or absence of other cardiovascular risk factors should be taken into account when deciding whether treatment is required or not.