Normal blood pressure values as perceived by normotensive and hypertensive subjects

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1 ORIGINAL ARTICLE Normal blood pressure values as perceived by normotensive and hypertensive subjects (2003) 17, & 2003 Nature Publishing Group All rights reserved /03 $ B Wizner, B Gryglewska, J Gasowski, J Kocemba and T Grodzicki Department of Internal Medicine and Gerontology, Jagiellonian University Medical College, Kraków, Poland In spite of considerable progress, the control of hypertension in most countries is still insufficient. One of the reasons may be the poor awareness of the blood pressure (BP) cutoff values that define hypertension. The aim of this report is to verify the hypothesis that patients with hypertension accept higher BP levels as normal. The study was performed during a street-based BP screening project carried out across Poland, in summer In 444 persons who voluntarily participated in Cracow s part of the project, BP was taken on the left arm, in the sitting position, after a minimum of 5 min of rest, using a semiautomated device (Digital Blood Pressure UA-702). A questionnaire investigated participants age, weight, height, level of education, history of hypertension and perception of normal values of BP. We compared measured BP values with those perceived as normal, and with the values recommended by WHO/ISH guidelines (o140/90 mmhg). To analyse the data we used Student s t-test and linear regression with adjustment for age and body mass index (BMI). Hypertensive subjects, compared with normotensives, were less aware of normal BP values (47.4 vs 83.9%, Po0.001, for systotic blood pressure, and 77.4 vs 88.4%, Po0.01, for diastotic blood pressure). Measured BP was positively related to BP values stated as normal. A similar relation was observed for age and BMI. In conclusion, poor awareness of normal BP values in hypertensives can be an important factor hindering better BP control. Education strategies might prove to be highly effective in helping to tackle the epidemics of hypertension. (2003) 17, doi: /sj.jhh Keywords: blood pressure; normal values; epidemiology Introduction The control of hypertension remains unsatisfactory worldwide, ranging from a few percent (6% in England), 1 3 to about 10% in Poland, 4 13% in Canada, 5 27% in the US. 6 Apart from other factors (ie economic), patients awareness of what hypertension is may play an important role. Currently accepted cutoff values for the detection of hypertension are 140 mmhg for systolic blood pressure (SBP) and 90 mmhg for diastolic blood pressure (DBP) Management schedules depend both on the level to which blood pressure (BP) is elevated and on the presence of other risk factors and target organ damage. Unfortunately, these criteria are not always observed. Moderate BP elevation ( /90 95 mmhg)firrespective of whether BP was taken at home or in the clinicfis quite often disregarded. The goal of the present work Correspondence: Dr T Grodzicki, Department of Internal Medicine and Gerontology, Jagiellonian University Medical College, 10 Sniadeckich St., Kraków, Poland. tomekg@mp.pl was to verify the hypothesis that hypertensive patients accept higher BP values as normal. Methods This study was conducted in Cracow during a streetbased BP screening programme, which was carried out in 100 cities across Poland between June and August 1997, in cooperation with a major insurance company. In all subjects who voluntarily participated, BP was taken with a semiautomated device (Digital Blood Pressure UA-702), in the sitting position, after a minimum 5 min of rest. Before the BP measurement, participants were questioned about their age, height and weight, and body mass index (BMI) was calculated from height and weight according to the formula BMI ¼ weight (kg)/(height (m)) 2. The participants were asked to fill out a selfadministered questionnaire, where in addition to questions concerning lifestyle, they were asked about normalfin their opinionfvalues of SBPand DBP. Data from persons who returned the questionnaire by the deadline (31 October 1997) were analysed.

2 88 According to their BP (WHO/ISH Guidelines) and based on the information from the questionnaires, patients were categorised into hypertensive and normotensive groups. Means were compared using Student s t-test, in proportion with the w 2 test. Relation between measured BP and level of patient-perceived normal BP values were modelled using analysis of regression with adjustment for age and BMI. Results We collected data of 444 participants (14.8% of 3000 screened), who returned the questionnaire. The characteristics of the studied group are shown in Table 1. The normotensive participants had a better awareness of normal SBP and DBP values than subjects with hypertension. The mean values of BP stated as normal by hypertensives were significantly higher than those reported by normotensives (for SBP: Table 1 Characteristic of studied population (n=444) Parameter Mean 7 s.d. Gender (% of women) 55.9% Age (years) Declared secondary or higher education 78.4% BMIX25 kg/m % Measured SBP mmhg Measured DBP Hypertension diagnosed in the past (n=133) BP awareness mmhg 29.9% vs mmhg; for DBP: vs mmhg, both Po0.001). The percentages of correct answers to questions about normal BP values (o140/90 mmhg) in hypertensive and normotensive groups were 83.9 vs 47.4%, Po0.001, and 88.4 vs 77.4%; Po0.01, for SBP and DBP, respectively. We found a linear relation between levels of BP declared as normal and the level of measured BP. This relation remained significant after adjustment for age and BMI (Figures 1 and 2). In similar analyses, a positive relation has been found with age (Figure 3) and BMI (Figure 4). Older and obese people more often accepted higher BP values as normal. There was no significant relation between gender and level of education and BP values declared as normal (Table 2). Similar results were obtained when previously used cutoff values (BPo160/95 mmhg) were employed. Discussion This report shows that hypertensive patients accept as normal higher BP values than the normotensives, and that measured values of BP are positively related to the level of cutoff values declared as normal by participants. A similar relation was observed for the age and BMI of studied persons. In our previous report, 12 we demonstrated that the BP level measured during a screening programme positively correlated with age and BMI, and negatively with the level of knowledge about hypertension. Patients are not only ignorant of when and Figure 1 The percentage of correct answers about normal SBP values (SBP o140 mmhg) according to measured SBP levels of studied subjects.

3 BP awareness 89 Figure 2 The percentage of correct answers about normal DBP values (DBFo90 mmhg) according to measured DBP levels of studied subjects. Figure 3 The percent of correct answers about normal BP values (o140/90 mmhg), according to the age. on what grounds the diagnosis of hypertension is made, 13,14 but are also unaware of their usual BP level. 15 This fact may be responsible for the low detection of the disease, worse compliance of the patient and ineffectiveness of treatment. Hence, the assessment of the patient s knowledge about hypertension should be a starting point of educational activities. Many studies focused on elderly people as a population that needs specific attention, since this group is characterised by a high prevalence of hypertension 16,17 and high efficacy of treatment, with respect to BP lowering, which in turn reduces the risks of cardiovascular diseases. 18,19 In our results, the knowledge of normal BP level has been inversely related to the age and BMI of studied

4 BP awareness 90 Figure 4 The percent of right answers about normal BP values (BPo140/90 mmhg), according to BMI of studied group. Table 2 BP values declared as normal (BPo140/90 mmhg) by sex and education level SBP o140 mmhg Correct answers (%) DBP o90 mmhg Correct answers (%) Gender Female (n=248) Men (n=196) Education level Elementary (n=97) Secondary/high school (n=347) persons. This indicates a low awareness about hypertension and the presence of the conjecture that BP cutoff values should increase with age. This contests the data from the Rotterdam study, where an exceptionally high awareness, also among elderly patients, has been observed. 20 Medical staff should focus their interest on these groups of patients and try to organise screening 21 and education programmes In recent years, the traditional role of the physician as an authority imposing treatment has been replaced by a new one in which patients assume more responsibility in the management of their disease. This evolution is observed especially in preventive health-care and chronic conditions such as hypertension or diabetes. Many studies have shown that educational interventions (eg home visits, groupclasses) might improve BP control, attachment to follow-up schedule and weight control On the other hand, a patient s knowledge is not only based on such an education strategy but frequently originates from information obtained from massmedia or relatives. 27,28 As the amount of health-care information rapidly expands, physicians have a dual responsibility of being aware of recent discoveries and implementing them into the clinical practice. Unfortunately, many studies have found discrepancies between recommendations in the published guidelines and everyday practice. 29 The awareness of values proposed in the guidelines is relatively poor, usually in the range of 30 60%. 30 Successful dissemination of consensus recommendations may be achieved only when accompanied by educational and behavioural interventions that enable physicians to modify their current practice. Their implementation into clinical practice takes time, particularly when they are controversial and contested by physicians. 31 This study has provided information that may be helpful to evaluate the educational needs of a society, especially in older and overweight people. A possible confounding of our results may arise from the recruitment of participants. As the study was a street-based screening, the subject s awareness may differ from that of the population in general. Nevertheless, the presented study revealed a significant relation between accepted BP levels and measured BP values, which might be one of the reasons for insufficient BP control. References 1 Sidabutar RP. Hypertension and its control in Indonesia. High Blood Press 1995; 4: Shalnova SA, Deev DA, Oganov GS, Zhukovsky GS. Arterial hypertension impact on mortality in Russia. Eur Heart J 1998; 19: P705.

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