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[Agreement in the measurement of blood pressure among different health professionals. Are mercury sphygmomanometers reliable?]
Abstract
To assess reliability in terms of inter-observer agreement of blood pressure (BP) readings. Various health professionals and measuring systems. Influence of observer's experience.
Observational, descriptive, cross-sectional study.
Urban health centre, Córdoba.
131 hypertensive, randomised patients, belonging to a functional care unit. 11 were excluded.
To reduce variability: course on the right way to take blood pressure, otoscope and verification of visual sharpness of observers, calibration and validation of measuring devices, limited time and blinding of measurements. 4 BP measurements per patient: 3 with mercury sphygmomanometer (2 simultaneously, one individual) and one with an automatic device. Descriptive, clinical and somatometric variables were gathered. Inter-observer agreement was evaluated through the intraclass correlation coefficient (ICC), the mean of differences method (MDM) and the simple concordance index (CI). An ICC > 0.75 was thought acceptable. A difference > 5 mmHg was thought clinically relevant (MDM and CI).
Acceptable consistency for MDM: alone, systolic and diastolic pressure of OBS 1/ OBS 2, bi-auricular, -6.1/+8.9 mmHg and -6.8/+5.8 mmHg. Less favourable results: for systolic and diastolic pressure: OBS 1/AUTO -20.9/25.0 and -16.4/15.1; OBS 2/AUTO -22.8/24.4 and -16.6/15.2. Remaining intervals always > 10 mmHg; CI > 0.75 in all comparisons except diastolic pressure OBS 1/AUTO and diastolic pressure OBS 2/AUTO (0.69 in both cases). 41% of comparisons were > 5 mmHg. No differences in less expert professionals were found.
Inaccuracy of the standard BP measurement method (mercury sphygmomanometer) for MDM and CI. Contradictory conclusions according to method of measurement. Differences not clinically acceptable.
... it-sampling fraction (f). When f is less than 0.35, Scott and Smith's predictor has higher increment in SMSE over TMSE than the Random Permutation Predictor. However, when f is greater than 0.35, the Random Permutation Predictor has higher percent increment in SMSE to TMSE than Scott and Smith's Predictor. Andre et al., 1987. Cavelaars et al., 2004. Ripolles et al., 2001. ...
... DBP Quarterly 0.032 77.15 mm Hg Andre et al., 1987. Cavelaars et al., 2004. Ripolles et al., 2001. ...
The best linear unbiased predictors (the Cluster mean, the Mixed model, Scott & Smith's predictor and the Random Permutation model) of selected important public health variables were evaluated in practical settings via simulation studies. The variables corresponded to measures of diet, physical activity, and other biological measures. The simulation evaluated and compared the mean square errors (MSE) of those four predictors. It estimated variances between subjects and days, and response errors for parameters defined over one year period, based on data from a large-scale longitudinal study, the Season Study. Then, it evaluated the relative MSE increase between predictors of the true subject's mean in various settings based on theoretical results. In addition, a simulation compared the theoretical and the simulated MSE for all four predictors. The difference in the MSE between predictors was illustrated in 2D plots.
Objective:
Accurate measuring of blood pressure is a vital step in both clinical and para-clinical settings. The aims of the present study were to evaluate the validity and inter-observer reliability of measured blood pressures by two trained observers and one expert supervisor in the PERSIAN Guilan cohort study (PGCS).
Participants and methods:
In a quasi-experimental study, two trained observers and one expert supervisor measured systolic and diastolic blood pressures (SBP and DBP) in 85 included participants. All measurements were done using Riester mercury sphygmomanometer as duplicate for each people.
Results:
Lack of validity in the total SBP (P = 0.017), DBP in age <50 years (P = 0.039), and DBP in BMI >25 (P=0.019) of first observer and total SBP (P = 0.045), SBP of male (P = 0.019), both SBP and DBP in age >50 years (P = 0.034, P = 0.012) and DBP in BMI <25 (P = 0.001) of second observer were seen. In addition, total inter-rater reliability was found as 12.2% and 27.2% in SBP and DBP, respectively. Age, sex and BMI categorized inter-observer reliability were not more than 15% in SBP of BMI <25 kg/m and 31.6% in DBP of female. The final inter-observer agreement after educational course was higher than 0.7 totally and in all categorical evaluations.
Conclusion:
Based on lack of validity in some conditions and low level of reliability, education of all observers to measure both SBP and DBP accurately is needed. This is more necessary to done before performing the high population surveys.
Objective: To compare two methods to calculate cardiovascular risk, PROCAM and Framingham using risk factors categories (hard events), in men between 45 and 65 years. Material and methods: We present a descriptive crossover study, made between January and December of 1999. The study was made in Primary Heatlh Care. We have examined all of men between 45 and 65 years, which belong to four family doctors in three health centers, without cardiovascular disease (n=402). For every man, it was analysed: age, diabetes mellitus, smoke, family history of premature coronary heart disease, systolic blood pressure, diastolic blood pressure, total cholesterol, LDL-cholesterol, HDL-cholesterol, tryglicerides. To compare both methods we used Pearson correlation coefficient, intraclass correlation coefficient (ICC), and the graphic representation was made with the Bland and Altman model. Results: Average cardiovascular risk was 8.56 ± 9.3% with PROCAM method versus 10.85 ± 6.8% with Framingham using risk factors categories. Pearson correlation coefficient was 0.859 (p< 0.001), ICC was 0.778 (p< 0.001). Average difference between PROCAM and Framingham using risk factors categories was -2.2% ± 4.9 p< 0.001. Conclusions: Even the correlation coefficients are higher than 0.75, and the average difference are 2.2%, there are a great variability in the individuals differences with the increase risk. Compared with Framingham using risk factors categories, for a low risk, PROCAM underestimates this risk, while, for a high risk PROCAM overvalues the risk.
Background
Instruments capable of accurately measuring blood pressure(BP) are absolutely necessary for the diagnosis and proper control of arterial hypertension. The use of automatic sphygmomanometers has become popular not only in clinics and hospitals, but also at home. The accuracy of each of these blood pressure meters should be approved by manufacturer- independent groups, following protocols established by the scientific community. The aim of this study is to evaluate the oscilometric automatic blood pressure device Accutorr Plus NIBP (Datascope Corporation, Mahwah, NJ, USA), with regard British Society of Hypertension protocol.
Patients and methods
One hundred and twenty adults (60 of which were diabetic) who attended a hospital outpatient clinic on consecutive occasions were included in the study. One hundred and twenty pairs of blood pressure measurements were obtained, half using the device being tested and the other half using a mercury Sphygmomanometer (as a control method). The same examiner took both readings from the same arm one after the other. The two measurements were compared by determining the difference between their real values.
Results
As far as systolic blood pressure (SBP) is concerned, differences of ≥5 mmHg reflected 24.4% of the readings. Differences of ≥10 mmHg and ≥15mmHg reflected 56.3% and 73.1% of the readings, respectively. All percentages are cumulative. Regarding diastolic blood pressure (DBP), the values which corresponded to each of the three groups were 39.5%, 67.2% and 90.7%, respectively. The means difference and standard deviation obtained from both test devices were notably homogeneous (SBP: 10.9 ± 7.4 and 10.7 ± 11.6 mmHg; DBP: 7.2 ± 5.3 and 7.1 ± 5.5 mmHg), without any statistically significant differences.
Conclusions
The Accutorr Plus NIBP automatic manometer obtained a D rating (not suitable for clinical use) for both SBP and DBP, according to the standards of the British Hypertension Society.
To assess the agreement between Primary Care (PC) doctors and a cardiology specialist in diagnosing left ventricular hypertrophy in the electrocardiograph (LVH-ECG) in hypertensive patients.
Cross-sectional, multicentre study.
Andalusian Primary Care Centres.
A total of 120 PC doctors who using a random sample selected patients of 35 years or more with AHT of at least 6 months of progression. PRIMARY VARIABLES: Demographic data, risk factors and cardiovascular diseases were recorded. The LVH-ECG was evaluated by applying Cornell voltage criteria, Cornell and Sokolow-Lyon product. The PC researchers read the ECG first and the cardiologist made a second reading blind.
A total of 570 patients (mean +/- SD of age, 65 +/- 11 years; 54.5% females); the LVH-ECG prevalence was 13.7% (95% CI, 10.8-16.6; 12.6% by Cornell and 1.6% by Sokolow-Lyon). The agreement in the diagnosis between the PC doctors and the cardiologist was 0.378 (95% CI, 0.272-0.486; disagreements in 15.5% of cases). The PC doctors slightly underestimated the LVH-ECG prevalence by Cornell and slightly overestimated it by the Sokolow-Lyon criteria. The agreement was also low for all of them (kappa = 0.367; 95% CI, 0.252-0.482, for Cornell, and kappa = 0.274; 95% CI: 0.093-0.454 for Sokolow-Lyon).
The agreement between the diagnosis by the PC doctors and the cardiologist was low. The implications of this study suggest the need to improve the reading of ECG among PC doctors. The use of computerised systems could be a good option.
Background. Blood pressure is traditionally measured in the doctor's office. Doubts concerning this method have led to use of automatic ambulatory device. Unpredictable differences between these methods motivated us to study this phenomenon. Material and methods. After device validation, 57 general practitioner screened 167 non-treated patients. An office blood pressure > 150 systolic and/or 95 diastolic led to standardised control. If still above 150 and/or 95, ambulatory measurements were made. Results. Systolic difference between office blood pressure and ambulatory measurements - day > 10 mm Hg occurred in 66% of the patients, diastolic > 5 mm Hg in 60%. Significant predictors for difference: different general practitioner, screening blood pressure, gender. Systolic also: stressed general practitioner and bad patient-doctor relationship. Diastolic also: age and patients aware of previous blood pressure value. Blood pressure < 150/95 was reached by 40% at office control, 32% after ambulatory measurements; 28% had sustained elevated blood pressure. Office blood pressure device aberration was £ 3 mm Hg in 95% control measures. Interpretation. Office blood pressure differs significant and unpredictable from, and therefore has to be supplemented by, ambulatory measurements in non-treated patients in general practice.
Despite widespread availability of a large body of evidence in the area of hypertension, the translation of that evidence into viable recommendations aimed at improving the quality of health care is very difficult, sometimes to the point of questionable acceptability and overall credibility of the guidelines advocating those recommendations.
The scientific community world-wide and especially professionals interested in the topic of hypertension are witnessing currently an unprecedented debate over the issue of appropriateness of using different drugs/drug classes for the treatment of hypertension. An endless supply of recent and less recent "drug-news", some in support of, others against the current guidelines, justifying the use of selected types of drug treatment or criticising other, are coming out in the scientific literature on an almost weekly basis. The latest of such debate (at the time of writing this paper) pertains the safety profile of ARBs vs ACE inhibitors.
To great extent, the factual situation has been fuelled by the new hypertension guidelines (different for USA, Europe, New Zeeland and UK) through, apparently small inconsistencies and conflicting messages, that might have generated substantial and perpetuating confusion among both prescribing physicians and their patients, regardless of their country of origin.
The overwhelming message conveyed by most guidelines and opinion leaders is the widespread use of diuretics as first-line agents in all patients with blood pressure above a certain cut-off level and the increasingly aggressive approach towards diagnosis and treatment of hypertension. This, apparently well-justified, logical and easily comprehensible message is unfortunately miss-obeyed by most physicians, on both parts of the Atlantic.
Amazingly, the message assumes a universal simplicity of both diagnosis and treatment of hypertension, while ignoring several hypertension-specific variables, commonly known to have high level of complexity, such as:
- accuracy of recorded blood pressure and the great inter-observer variability,
- diversity in the competency and training of diagnosing physician,
- individual patient/disease profile with highly subjective preferences,
- difficulty in reaching consensus among opinion leaders,
- pharmaceutical industry's influence, and, nonetheless,
- the large variability in the efficacy and safety of the antihypertensive drugs.
The present 2-series article attempts to identify and review possible causes that might have, at least in part, generated the current healthcare anachronism (I); to highlight the current trend to account for the uncertainties related to the fixed blood pressure cut-off point and the possible solutions to improve accuracy of diagnosis and treatment of hypertension (II).
Indices of cardiovascular morbidity and mortality in the Balearic Islands in Spain are poor. We decided to investigate the prevalence of the main cardiovascular risk factors (CRFs) and of different cardiovascular diseases in inhabitants of these islands aged 35-74 years. SUBJETS AND METHOD: A population-based descriptive cross-sectional study was used. The Balearic Islands were divided into 14 sectors, each with three or four participating general practitioners (GPs). A random selection of 40 patients registered with each GP was made. Patients were contacted in the surgery or by mail or telephone. Each GP administered a questionnaire on the patients' family and personal history of cardiovascular disease and CRFs such as levels of smoking and physical activity, carried out anthropometric and blood pressure measurements, and requested blood glucose, cholesterol, and cholesterol fraction measurements.
The study included 1685 individuals. Some 27% smoked (men 36.9%, women 18.7%), 47.8% had high blood pressure (men 52.3%, women 43.4%), 24.2% had hypercholesterolemia (men 24.4%, women 24.1%), 11.7% had diabetes mellitus (men 15.3%, women 8.4%), 27% were obese (men 24.8%, women 29%), 40.1% were overweight (men 48.3%, women 33.4%), and 43.1% of men and 45.6% of women were sedentary. Two or more CRFs were observed in 58.4%, and 9.8% had a diagnosed cardiovascular disease. The Framingham method gave a higher estimate of cardiovascular risk in all age groups than the REGICOR method.
The prevalence of the main CRFs in the Balearic Islands is high, implying a high risk profile. Dietary and lifestyle interventions, and preventive measures are recommended.
Objective
. To evaluate the degree of inter-observer concordance in the blood pressure figures taken by a nurse and a doctor with a mercury sphygmomanometer and by the patient with a semi-automatic device.
Design
. Observational, crossover study.
Setting
. A rural health centre.
Patients
. 318 people selected by systematic sampling.
Interventions
. Pressure was taken in different ways by 3 different «observers» (0): the patient with a semi-automatic device (01), a nurse (02) and a family doctor (03). Inter-observer concordance was assessed through the Intra-class Correlation Coefficient (ICC) and the kappa index.
Measurements and main results
. 42.1%, 41.8% and 44.3% of patients had high blood pressure (≥ 140/90 mmHg) according to 01, 02 and 03, respectively. 33% were known to be hypertense. The ICC for systolic pressure was 0.81 (95% CI, 0.75-0.87) between 01 and 02; 0.84 (CI, 0.78- 0.90) between 01 and 03; and 0.87 (CI, 0.82-0.92) between 02 and 03. The ICC for diastolic pressure was 0.67 (CI, 0.59-0.75), 0.72 (CI, 0.64-0.79) and 0.79 (CI, 0.72-0.86) for 01-02, 01- 03 and 02-03, respectively. The kappa index was 0.53 (CI, 0.43-0.62) for 01-02; 0.60 (CI, 0.51- 0.68) for 01-03; and 0.67 (CI, 0.58-0.75) for 02-03.
Conclusions
. Inter-observer concordance was good, with no substantial differences between the measurements made by the different observers. As the figures determined by the semiautomatic device were reliable, this is a good option for the follow-up and monitoring of hypertense patients.
In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old. Such investigations are often analysed inappropriately, notably by using correlation coefficients. The use of correlation is misleading. An alternative approach, based on graphical techniques and simple calculations, is described, together with the relation between this analysis and the assessment of repeatability.
The aim of this study was to test two of the same models of portable automatic devices for monitoring blood pressure over 24 hours. These devices were the Spacelabs 5200 (Kontron 1 and Kontron 2).
A mercury shygmomanometer was used as reference measurer. To validate Kontron 1, 22 persons (10 males and 12 females) of 45 +/- 12 years of age were selected. For Kontron 2, 25 subjects (12 males and 13 females) of 44 +/- 17 years of age were chosen.
The results expressed as arithmetic mean and standard deviation were (manual vs Kontron 1); systolic blood pressure (SBP) 139 +/- 19 mmHg vs 135 +/- 16 mmHg, p less than 0.05; diastolic (DBP) 96 +/- 12 mmHg vs 93 +/- 12 mmHg, p less than 0.05, heart rate (HR) 77 +/- 13 ppm vs 76 +/- 14 ppm, NS. The correlation between the two methods was: SBP r = 0.870; DBP r = 0.875 and HR r = 0.949. The results of Kontron 2 were: SBP 137 +/- 17 mmHg vs 130 +/- 15 mmHg, p less than 0.05; DBP 93 +/- 11 mmHg vs 94 +/- 11 mmHg, NS; HR 75 +/- 10 ppm vs 73 +/- 12 ppm, NS. The correlations were: SBPr = 0.820; DBP r = 0.877 and HR r = 0.847.
The Spacelabs 5200 automatic blood pressure monitoring underestimates systolic blood pressure while diastolic blood pressure and heart rate are reliable according to international norms.
We assessed the agreement between 2 methods of data gathering of particular interest in urology: patient questionnaire and examination vs. frequency-volume charts. One hundred consecutive patients consulting our out-patient clinic were chosen for this study; 88 completed the study. Urinary frequency and bladder capacity were evaluated in each patient by using the above methods. The agreement between different methods of measurement was assessed by determining whether the 2 methods were interchangeable, a condition occurring if results of both methods fall within predetermined limits of variability. The results showed poor agreement between subjectively estimated urinary frequency and chart-determined urinary frequency. Moreover, different methods of measuring bladder capacity (endoscopic vs. chart) gave different results. Since chart-determined data are probably a more valid indication of urinary habits, we suggest that frequency-volume charts should be used more often in the investigation and follow-up of patients with micturition disorders.
With the increasing manufacture of expensive systems for the measurement of ambulatory blood pressure there is a need for potential purchasers to be able to satisfy themselves that the systems have been evaluated according to agreed criteria. The British Hypertension Society has, therefore, drawn up a protocol of requirements for the evaluation of these devices. This protocol incorporates many features of the American National Standard for Non-Automated Sphygmomanometers but includes many additional features, such as strict criteria for observer training, interdevice variability testing before and after a month of ambulatory use, and a new system of analysis which permits the test system to be graded. It is recommended that manufacturers of ambulatory blood pressure measuring devices should obtain an unbiased evaluation according to a recognized standard before a device is marketed.
The intraclass correlation coefficient (rI) has been advocated as a statistic for assessing agreement or consistency between two methods of measurement, in conjunction with a significance test of the difference between means obtained by the two methods. We show that neither technique is appropriate for assessing the interchangeability of measurement methods. We describe an alternative approach based on estimation of the mean and standard deviation of differences between measurements by the two methods.
The degree of concordance between observers in the quantitative case is represented by the interclass correlation. The practical interest of computing concordance indexes, particularly in the planning phase of multicentric studies is discussed.
The value of nocturnal minute-by-minute urine was analyzed for the detection of microalbuminuria in high blood pressure.
Urinary albumin excretion (UAE) was measured by immunonephelometry in 70 patients with essential arterial hypertension (34 males, mean age 44 +/- 5 years, body mass index [BMI] 28 +/- 4, clinical blood pressure [BP] 157 +/- 12/97 +/- 7 mmHg) and 12 healthy normotensive controls (5 males, mean age 38 +/- 4 years, BMI 27 +/- 3; clinical BP 126 +/- 12/79 +/- 5 mmHg). Both 24 hours urine as well as nocturnal urine were collected over 2 days. The intraindividual variability was evaluated by calculation of the intraclass correlation coefficient and by the Bland and Altman method.
Mean 24-hour UAE was 24.7 +/- 41.9 micrograms/min, greater than nocturnal urine (17.7 +/- 32.8 micrograms/min) (p < 0.05). The UAE rate was significantly greater in the hypertensive patients than in the controls (p < 0.01) for both the 24-hour and nocturnal urine. The intraindividual variability estimated as the percentage of repeatability was 35% for 24-hour UAE and 43% for nocturnal UAE, being slightly higher values than those observed in the controls. Microalbuminuria was detected in 17 (24%) of the patients in 24-hour samples while in the nocturnal urine 12.12 or 10 patients were found according to whether the threshold considered was 14 micrograms/min, 14.9 micrograms/min or 20 micrograms/min, respectively. While the specificity in nocturnal minute-by-minute urine was 98% and the positive predictive value was 0.91 for any of the thresholds considered, sensitivity ranged from 59% for the higher threshold (20 micrograms/min) to 70% for the lower threshold (14 micrograms/min).
The determination of microalbuminuria in minuted nocturnal urine in patients with essential arterial hypertension is less sensitive than that determined in 24-hour urine.
To evaluate the validity of blood pressure measurement by studying the presence of preference bias in last digits and also of the bias which tends to situate measurements below the established limit. To evaluate the interobserver (doctor-nurse) reliability of the measurements.
A cross-sectional [correction of crossover] observation study with descriptive and analytic components.
A nursing station in the Health Centre.
The patients who attended the nursing station by appointment during the months of September and October 1993.
The patients who attended the nursing station by appointment had their blood pressure measured by a doctor or nurse in a random fashion. We detected a preference in last digits, which was very significant for both systolic and diastolic pressure (p < 0.0001). The tendency to reduce diastolic figures to below the preestablished limit of pressure was also very significant (p < 0.05). The nurse found lower figures than the doctor, with a very significant difference for diastolic pressure (p < 0.001). The index of kappa concordance between nurse and doctor on evaluating whether pressure was high or not was 0.4864, with a C.I. of 95%, from 0.3530 to 0.6198.
The existence of two important biases in the measurements of pressure questions their validity. Additionally the significant difference between the pressure averages and the low concordance poses a serious question over the interobserver reliability and should make us restate blood pressure measurement and the treatment of patients suffering Hypertension.
The inherent variability of blood pressure means that the accuracy of a small number of clinic readings in estimating the true blood pressure is limited. In many patients, a clinic visit provokes an increase in blood pressure such that they may be misclassified as being hypertensive (white coat hypertension). This applies to about 20% of hypertensives. Ambulatory monitoring has the potential to overcome these limitations. The white coat effect may still occur in patients taking antihypertensive medications, although in some cases medication may lower the clinic pressure without affecting the ambulatory pressure. The diurnal rhythm of blood pressure is another major source of variability and is influenced by both extrinsic and intrinsic factors. Its pathologic significance is unclear. Antihypertensive medication generally lowers the set point of blood pressure but has relatively little effect on variability.
To check the validation of the precision in measuring arterial pressure (AP) of an automatic non-invasive machine for out-patient monitoring of arterial pressure, the ACP-2200, comparing the sequential with the simultaneous method in line with the criteria of the Association for the Advancement of Medical Instrumentation.
A comparative crossover study.
Primary Care. "La Orden" Health Centre, Huelva.
86 individuals, 42 men and 44 women of all ages, both hypertense and not, and without any antihypertension treatment, with SAP intervals between 99 and 160 mmHg and DAP between 59 and 105 mmHg, selected at random from the on-demand consultations.
Three AP readings were made with a manual apparatus for reference (a mercury sphygmomanometer) and three simultaneously with the ACP-2200 and the manual apparatus placed in a T on the cuff. The AP means obtained were compared and the mean calculated. The standard deviations of the paired differences between the APs obtained with the ACP-2200 and with the manual method, both in the sequential and simultaneous form, as well as Pearson's lineal correlation coefficient, were all calculated. The means of the paired differences and the standard deviations between the automatic and manual apparatuses were, for the SAP, 1.52 +/- 4 (r = 0.96) and 0.66 +/- 3.38 (r = 0.97) (sequential and simultaneous, respectively) and, for the DAP, 0.86 +/- 2.84 (r = 0.98) and 0.64 +/- 1.73 (r = 0.99) (sequential and simultaneous, respectively). All the values of p were inferior to 0.001.
The ACP-2200 complies with the validation criteria for the two methods used, with the simultaneous method being recommended for use.
To determine ambulatory and home blood pressure means and distributions in relation to clinic blood pressure in a general population.
We obtained a random sample of 2400 subjects stratified by sex and 10 year age groups to be representative of residents aged 25-64 years of the city of Monza. Participation rate was 69% (1651 subjects). Blood pressure measurements consisted of clinic blood pressure (average of three measurements, sphygmomanometry), home blood pressure (average of morning and evening measurements, semiautomatic device) and ambulatory blood pressure (automatic readings at 20 min intervals, Spacelabs 90207). Clinic blood pressure was obtained both before and after home and ambulatory blood pressures. Data analysis did not include 213 subjects receiving antihypertensive drug treatment and was therefore limited to 1438 participants.
In the 1438 subjects, clinic, home and ambulatory blood pressure showed a normal-like distribution, with a taller peak and a narrower base for ambulatory than for home and clinic values. Clinic, home and ambulatory blood pressures were significantly related to each other (P always < 0.001). The means of the two clinic blood pressures obtained on consecutive days were superimposable (127.4 +/- 17.0/82.3 +/- 9.8 and 128.2 +/- 16.5/81.9 +/- 9.9 mmHg) and both were markedly higher than home and 24 h average blood pressures (8.2 mmHg), which were similar to one another. The differences between clinic and home or 24 h average blood pressure were similar in both sexes but increased with increasing age and clinic blood pressure values. The influence of clinic blood pressure values on the clinic-ambulatory or clinic-home blood pressure differences was more important than age. Although higher than the 24 h average value, daytime average blood pressure was also lower than clinic blood pressure. Night-time blood pressure was markedly lower than the daytime value in both sexes and at all ages.
Data from a large and unbiased sample of a general population show that home and 24 h or daytime average blood pressures are much lower than clinic blood pressure. The relatively close correlation between blood pressure values measured with the different methods used has allowed calculation of home and ambulatory blood pressure values corresponding to the accepted upper limit of normality of clinic blood pressure (140/90 mmHg). The upper limit of normality for the population was for both home and ambulatory blood pressures in the range 120-130 and 75-81 mmHg for systolic and diastolic values, respectively, with slight differences depending on sex and age. Taking 140/90 mmHg as the upper normal limit of the population is therefore an error that leads to individuals whose home or ambulatory blood pressures are high being considered as normotensive.
To evaluate a self-measuring blood pressure (BP) monitor, the OMRON-HM 722C.
Based on the protocol of the British Hypertension Society (BHS).
Urban health centre.
A sample of 120 people (69 women) excluded those with a brachial perimeter under 24 centimetres or over 32.
Each subject had four BP measurements in succession, separated by a minute: a) Manually, with a mercury sphygmomanometer (MSM); b) with self-measurement monitor; c) with self-measurement monitor; d) with MSM. Means and SD of systolic and diastolic pressures, means and SD of the differences and a graphic representation of these by the Bland and Altman method, were calculated. The cumulative percentages of differences the same as or below 5, 10 and 15 mm Hg were calculated. 89.1% of systolic BPs, and 92.5% of diastolic BPs, showed mean differences between monitor and observer equal to or below 5 mm Hg. The size of the differences was grade A in both cases, according to the BHS criteria.
The OMRON-HM 722C self-measuring monitor could be useful for self-measurement of BP at home by primary care patients.
OBJECTIVE: We evaluated three devices for self-measurement of blood pressure - the Omron HEM-705CP, the Philips HP5332 and the Nissei DS-175 - according to the revised protocol of the British Hypertension Society (BHS). The results were also analysed according to the criteria for accuracy of the revised standard of the Association for the Advancement of Medical Instrumentation (AAMI). DESIGN: The revised BHS protocol is divided into two parts. Part I, the part applicable to this study, comprises the main validation procedure and has five phases: Before-use device calibration; in-use (field) phase; after-use device calibration; static device validation; report of evaluation. METHODS: Three models of each device passed the before-use device calibration test, after which they entered the in-use phase, which involved use of the three recorders for a month; inter-device calibration was assessed again at the end of the month. There was no difference in calibration testing between the three models of each device, and therefore one of each was selected randomly; the main validation test was carried out in 85 subjects with a wide range of pressures, and the results were analysed according to the BHS grading system from A to D. RESULTS: The Omron HEM-705CP achieved an overall B/A grading and fulfilled the AAMI accuracy criteria; the Philips HP5332 achieved an overall C/A grading and failed the AAMI accuracy criteria for measuring systolic pressure; the Nissei DS-175 achieved an overall D/A grading and failed the AAMI accuracy criteria for measuring systolic pressure. When the BHS and AAMI criteria were applied to tertiles of pressure (low-pressure range < 130/80 mmHg; medium-pressure range 130-160/80-100 mmHg; high-pressure range > 160/100 mmHg) all three devices were less accurate in the high-pressure range: the Omron HEM-705CP achieved C/B grading while continuing to fulfil the AAMI criteria; the Philips HP5332 dropped to D grading for systolic pressure and the Nissei DS-175 achieved a lower D grading for systolic pressure. The mean and standard deviation of the first mercury sphygmomanometer measurements were 148+/-35/88+/-22 mmHg. Acceptability by the users was good and the manufacturer's manual was satisfactory for all three devices. CONCLUSIONS: On the basis of these results, the Omron HEM-705CP was the most accurate of the three devices tested, achieving Grade B for systolic and Grade A for diastolic pressure, as well as fulfilling the AAMI criteria for accuracy for both systolic and diastolic pressure. It can therefore be recommended for the clinical measurement of blood pressure and is the first inexpensive device to satisfy the accuracy criteria of these protocols.
In the present study we evaluated the influence of the observer's status--physician or nurse--on blood pressure levels and the relationship among clinic blood pressure measurement with ambulatory blood pressure and left ventricle mass.
Cross sectional study performed in seven primary care centers. Participating physicians and nurses were trained for blood pressure measurement prior to the study and subsequently retrained at 3 month intervals during the study. Patients included in the study were 122 subjects with mild to moderate hypertension who underwent the following study protocol: a) measurement of clinic blood pressure by physician and nurse, in an independent fashion, on 3 visits; b) clinic-epidemiologic questionnaire; c) conventional hematological and biochemical study; d) electrocardiogram; e) 24-hour ambulatory blood pressure monitoring, f) M-mode and Doppler echocardiography (only in 58 subjects).
Nurse-measured blood pressure levels were higher than those determined by physicians (mean differences: 3.9 [6.7] mmHg in systolic blood pressure and 2.6 [5.4] mmHg in diastolic blood pressure). The blood pressure level differences between the two observers were higher in female patients and subjects with low educational level, independently of the observer's gender. Nurse-measured blood pressure was more closely related to ambulatory blood pressure and left ventricle mass than physician-measured blood pressure.
Nurse-measured blood pressure levels are lower than those determined by physicians and more closely related to ambulatory blood pressure and left ventricle mass than physician-measured blood pressure. These data support that nurses, instead of doctors, should routinely measure blood pressure in primary care centers.
To evaluate the degree of inter-observer concordance in the blood pressure figures taken by a nurse and a doctor with a mercury sphygmomanometer and by the patient with a semi-automatic device.
Observational, crossover study.
A rural health centre.
318 people selected by systematic sampling.
Pressure was taken in different ways by 3 different "observers" (0): the patient with a semi-automatic device (01), a nurse (02) and a family doctor (03). Inter-observer concordance was assessed through the Intra-class Correlation Coefficient (ICC) and the kappa index.
42.1%, 41.8% and 44.3% of patients had high blood pressure (> or = 140/90 mmHg) according to 01, 02 and 03, respectively. 33% were known to be hypertense. The ICC for systolic pressure was 0.81 (95% CI, 0.75-0.87) between 01 and 02; 0.84 (CI, 0.78-0.90) between 01 and 03; and 0.87 (CI, 0.82-0.92) between 02 and 03. The ICC for diastolic pressure was 0.67 (CI, 0.59-0.75), 0.72 (CI, 0.64-0.79) and 0.79 (CI, 0.72-0.86) for 01-02, 01-03 and 02-03, respectively. The kappa index was 0.53 (CI, 0.43-0.62) for 01-02; 0.60 (CI, 0.51-0.68) for 01-03; and 0.67 (CI, 0.58-0.75) for 02-03.
Inter-observer concordance was good, with no substantial differences between the measurements made by the different observers. As the figures determined by the semi-automatic device were reliable, this is a good option for the follow-up and monitoring of hypertense patients.
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