Published online before print February 22, 2007, doi: 10.1161/01.STR.0000259733.43470.27
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(Stroke. 2007;38:1304.)
© 2007 American Heart Association, Inc.
Original Contributions |
The Relation Between Knowledge About Hypertension and Education in Hospitalized Patients With Stroke in Vienna
From the Department of Neurology (D.S., S.G., E.A., W.L.), Medical University of Vienna, Austria; and the Department of Neurology (W.L.), Hospital Barmherzige Brueder, Vienna, Austria.
Correspondence to Wolfgang Lalouschek, MD, Medical University of Vienna, Department of Neurology, Waehringer Guertel 18-20, 1090 Vienna, Austria. E-mail wolfgang.lalouschek{at}meduniwien.ac.at
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Abstract |
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Background and Purpose— Knowledge about hypertension and its control influences blood pressure control in patients with hypertension. We assessed these parameters in a large cohort of patients with ischemic stroke or transient ischemic attack and analyzed their association with educational attainment.
Methods— Five hundred ninety-one consecutive patients with stroke with a medical history of hypertension were interviewed about knowledge concerning hypertension within a multicenter hospital-based stroke registry. We analyzed answers in relation to educational level with multivariate logistic regression adjusted for age and sex.
Results— Seventy-seven percent of the patients stated to have known about hypertension being a risk factor for stroke, but only 30% felt at increased risk of stroke. Less than half (47%) could identify 140 mm Hg or less as the maximum tolerated systolic blood pressure, and 53% had their blood pressure only controlled monthly or less often. Knowledge of possible consequences of myocardial infarction, nephropathy, peripheral vascular disease, and retinopathy was 64%, 20%, 11%, and 16%, respectively. Approximately half of patients were acquainted with the nonpharmacologic treatment options of physical activity (49%), reduction of salt intake (54%), and reduction of caloric intake (48%), whereas relaxation techniques were only known to 17%. Adherence to those treatment options ranged from 42% to 67%. Educational level was significantly associated with knowledge of increased risk, possible consequences of hypertension, and knowledge about nonmedication treatment options.
Conclusion— Knowledge in our population was insufficient and partly associated with educational level, leaving much room for improvement by educational campaigns. Furthermore, we found a gap between knowledge of the increased risk for stroke in patients with hypertension and awareness of their own risk.
Key Words: education • hypertension • ischemic • socioeconomic status • stroke
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Introduction |
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Hypertension is the leading modifiable risk factor for stroke, being causally involved in nearly 70% of all stroke cases.1 Sixty percent of all patients with stroke report a history of arterial hypertension2,3 and up to three fourths of those with known and treated hypertension are not adequately controlled.4,5 It has been estimated that nearly half (45%) of all strokes among subjects with treatment for hypertension might be attributed to poorly controlled hypertension.6,7 Moreover, a meta-analysis of 17 randomized, controlled trials demonstrated a 38% reduction of stroke by blood pressure lowering.8 This leaves plenty of room for population-based strategies of blood pressure control to produce a substantial relief in the global burden of stroke.
In hypertensive subjects, awareness about their increased risk for stroke is connected to higher compliance in stroke prevention practices.9 However, patients at risk for cerebrovascular disease tend to underestimate their risk, especially if they are currently without symptoms and lack direct experience with the questioned event. Previous studies showed that only a minority of individuals at an increased risk for stroke or already under investigation for possible stroke were aware of their increased risk.9,10 In these reports, socioeconomic status was an independent predictor of awareness, a higher education being linked with increased awareness. We sought to assess awareness for hypertension and individual knowledge about it in a patient population with transient ischemic attack (TIA) or ischemic stroke and a history of arterial hypertension. We also investigated whether socioeconomic status is associated with knowledge about hypertension.
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Methods |
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Patients
This study was nested in the Vienna Stroke Registry, a prospective population-based registry of patients admitted to one of the eight participating neurologic departments in Vienna, Austria, serving a community of 1.9 million people. Details of the Vienna Stroke Registry have been published elsewhere.11 In short, all patients with TIA or ischemic stroke, who were admitted within 72 hours of symptom onset, were prospectively documented on the basis of informed consent. We recorded clinical and neurologic parameters (National Institutes of Health Stroke Scale, Scandinavian Stroke Scale, modified Rankin Scale, Barthel Index), results of technical and laboratory investigations, and performed a structured interview for demographic factors, medical history, socioeconomic circumstances, and knowledge about risk factors. The diagnosis of stroke was confirmed by cerebral computed tomography or magnetic resonance imaging scan. Followup was done at 3, 12, and 24 months after the qualifying event. Recruitment was done between December 1999 and December 2001. The protocol was approved by the local ethics committee.
Educational Level
We chose education as a marker of socioeconomic status, because it is reliably recalled, can be easily quantified in terms of numbers of years, and reverse causation does not confuse interpretation.12 We divided patients into five categories: no basic school education, secondary school graduation, apprenticeship, upper secondary school graduation, and university or college graduation.
Assessment of Awareness and Knowledge About Hypertension
The questions for assessment of awareness and knowledge about hypertension are given in Table 1.
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Statistical Analysis
Statistical analysis was conducted with SPSS 11.0. Continuous data are given as means. Categorical data are given as counts and percentages. Binary and categorical data were analyzed using contingency tables and a 
2 statistic. To assess the influence of socioeconomic status on knowledge, we applied multivariate logistic regression and adjusted for age and sex. Probability values of <0.05 were considered statistically significant. Apprenticeship was used as the reference category in the logistic regression model. The Hosmer-Lemeshow test was used to assess the model fit; probability values >0.1 indicate an agreeable model fit.
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Results |
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Study Population
Of 1250 patients admitted with ischemic stroke or TIA between December 1999 and December 2001, 868 (70%) reported a history of arterial hypertension. One hundred twenty-one patients were excluded, because their level of education was unknown. Of the remaining 747 patients, 591 (68% of the population with hypertension) completed the questionnaire concerning knowledge about hypertension and were available for further analysis. Compared with the whole hypertensive population, they did not differ in gender distribution (44% female in either group), but they were significantly younger (median 70 versus 73 years, P<0.001). Characteristics of the study population are summarized in Table 2. Three hundred thirty-one (44%) were female and 260 (56%) were male. Female sex was associated with a lower level of education (P<0.001). Mean age was 69 years (SD, 12; median, 70; interquartile range, 60 to 78). There were no differences in age or severity of the event (TIA or minor stroke versus major stroke) defined by educational level. Distribution of cardiovascular risk factors according to education is given in Table 3. There was no difference in prevalence of diabetes, current smoking, hypercholesterinemia, prior stroke, or coronary artery disease between the groups.
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Awareness of and Knowledge About Arterial Hypertension
Results of assessing awareness and knowledge about arterial hypertension are summarized in Table 4. Seventy-seven percent of patients claimed to be aware of hypertension as a risk factor for stroke, but knowledge was highly significantly correlated with educational level (P<0.001). Only 30% had considered themselves at increased risk for stroke and 34% felt themselves at increased risk for myocardial infarction. There was no difference between educational groups. Less than half of the patients with hypertension (47%) stated a systolic blood pressure of or below 140 mm Hg as the upper limit but only 20% of patients stated this without a basic school education (P<0.05 compared with the reference category). Knowledge of the maximum tolerated diastolic blood pressure was the same throughout the groups and comparably high with 81% of patients stating a value of 90 mm Hg or below. Fifty-three percent had their blood pressure controlled at least weekly, whereas the remaining 47% controlled it monthly or less often. Patients without a basic school education had a significantly lower frequency of blood pressure measurements than the others (P<0.05 compared with the reference category). Three fourths (76%) of the patients stated they owned a blood pressure meter, but only 63% used it.
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Knowledge of other possible consequences of hypertension, namely myocardial infarction, nephropathy, peripheral vascular disease, and retinopathy, were significantly associated with educational attainment. Knowledge about these consequences ranged from 64% for myocardial infarction to 11% for peripheral vascular disease. Concerning nonpharmacologic options for lowering blood pressure, there were significant differences defined by educational level as well; the higher the educational level, the more patients were likely to know about physical activity, reduction of salt intake, reduction of caloric intake, and relaxation techniques. Knowledge about these options ranged from 17% (relaxation techniques) to 54% (reduction of salt intake). When asking about adherence to these lifestyle modifications, 37% to 66% affirmed to do so.
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Discussion |
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Awareness and knowledge about hypertension in patients with stroke with a history of hypertension were suboptimal in our population. Although three fourths (77%) stated they had known about the increased risk for stroke associated with hypertension, actually less than one third (30%) felt themselves at increased risk. This implies that more than half of patients who affirmed the question "Do you have a medical history of hypertension?" and had received the information "High blood pressure is a risk factor for stroke" neglected possible consequences for their own risk. The level of awareness thus was lower than reported previously. Carroll et al, who interviewed patients with stroke/TIA, found 43% of the hypertensives were aware of their own risk.13 Samsa et al, who interviewed 1261 patients with increased stroke risk, found 41% of them were aware of it.9
Educational level markedly influenced knowledge of hypertension as a risk factor of stroke. It steadily increased from 54% in patients without a basic school education to 89% of patients with a college degree. Interestingly, missing awareness of being at an increased risk for stroke and myocardial infarction was the same throughout the groups. Because patients with higher education were more likely to know about the connection between stroke and hypertension, this implies that they also more often denied this fact for themselves. To our knowledge, we are the first to investigate "knowledge" and "awareness" separately, but our results indicate that these are not necessarily linked to each other.
Notably, only half of the patients were able to state the maximum tolerated systolic blood pressure (or a value below), which seems surprisingly low but is consistent with a survey in the United States in 2005, where 49% could name the target values of blood pressure.14
Questioning about consequences of hypertension revealed another deficit: myocardial infarction was known by 64% of the patients followed by nephropathy—known by one of five—whereas peripheral vascular disease and retinopathy reached only 11% and 16%, respectively. Compared with knowledge in older Americans in a recent report, in which 86% could identify heart disease and 49% kidney failure as a consequence of hypertension, this is clearly lower.15 Again, there were highly significant differences between the different educational groups.
Nonpharmacologic treatment options by adoption of healthy lifestyles have been recommended as an indispensable part of management in patients with hypertension.16 Weight reduction was shown to lower blood pressure with a 5 to 20-mm Hg systolic blood pressure reduction per 10-kg weight loss,17,18 as does reduction of sodium intake (2 to 8 mm Hg)19–21 and regular physical activity (4 to 9 mm Hg).22,23 All named treatment options were known by approximately half of our population with exception a fourth option we asked—practicing relaxing techniques—which was only familiar to 17% of patients. Again, there were clear differences between the educational groups. Consecutively asking about adherence to these lifestyle modifications showed that better knowledge is not necessarily related to a better practice; the only statistical significance according to educational level concerned reduction of salt intake, whereas the other three options were adopted by a maximum of nearly 40% of patients in all educational levels.
In summary, there is much room for improvement in hypertensive patients’ awareness of and knowledge about hypertension, its consequences, and nonpharmacologic ways to control it. Moreover, it seems to be important to help patients transfer their knowledge adequately into practice. Perceived risk is one of the key factors for promoting behavioral changes; a person perceiving risk for some adverse event as high is more likely to take preventive action to reduce the risk.10 For our patients, this could, for example, mean providing individualized risk feedback, which was shown to be effective in increasing perceived stroke risk among patients who had underestimated their stroke risk.10 For better adherence to lifestyle modifications, Burke et al found a structured "modification program" to be effective.24
Our results do not only point out a strong need for improvement of knowledge in people at increased risk for cerebrovascular disease, but also the need of increasing awareness of their individual risk. Because the drugs for effective lowering of blood pressure exist, education of affected patients is an important target to convert the possible 40% risk reduction into reality for all patients with hypertension.
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Acknowledgments |
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Disclosures
None.
Received June 22, 2006; revision received October 20, 2006; accepted October 30, 2006.
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