(Hypertension. 2000;35:814.)
© 2000 American Heart Association, Inc.
Scientific Contributions |
From the Departments of Epidemiology and Biostatistics (C.T.M. van R., J.C.M.W., A.H., D.E.G) and Public Health (C.T.M. van R., H. van de M., J.P.M.), Erasmus University Medical School Rotterdam, Rotterdam, the Netherlands; and Julius Center for Patient Oriented Research (D.E.G.), Utrecht University Medical School, Utrecht, the Netherlands.
Correspondence to Dr Diederick E. Grobbee, Department of Epidemiology and Biostatistics, Erasmus University Rotterdam, PO Box 1738, 3000 DR Rotterdam, the Netherlands. E-mail d.e.grobbee{at}jc.azu.nl
| Abstract |
|---|
|
|
|---|
55 years old and living in a district of Rotterdam. The prevalence of
hypertension was based on blood pressure levels (
160/95
mm Hg) and the use of blood pressurelowering medication for the
indication of hypertension, type of treatment, and control of
hypertension. Systolic blood pressure rises with age, whereas
diastolic blood pressure declines. The prevalence of
hypertension increases with age and was higher among women (39%) than
among men (31%). About 80% of the hypertensives were aware of having
hypertension, and 82% of the 80% were treated. For 70% of them,
treatment was adequate with reference to conservative criteria.
Hypertension was more prevalent among persons not living in a home for
the elderly, for more-educated men, and for less-educated women.
Persons without a partner and men living in a home for the elderly had
a higher risk of being unaware of or of not being treated for existing
hypertension. Treatment was more often successful among those living in
a home for the elderly. The prevalence of hypertension was higher among
older women and increased with age in both genders. A large proportion
of hypertensive elderly persons were aware and were successfully
treated for hypertension. The degree of awareness and control appeared
to be affected by sociodemographic factors. More importantly, the
majority of hypertensives did not have their hypertension well
controlled. This group requires more attention by medical
practitioners to reduce the burden of
cardiovascular diseases in elderly persons.
Key Words: hypertension, detection and control age sociodemographic factors epidemiology
| Introduction |
|---|
|
|
|---|
We provide data on the prevalence, treatment, awareness, and control of hypertension among an elderly Dutch population. In addition, we examined whether there are socioeconomic and demographic differences in the diagnosis and treatment of hypertension.
| Methods |
|---|
|
|
|---|
55 years old and living in 1 defined geographic area in
Rotterdam, the Netherlands. The rationale and design of the study have
been described elsewhere.9 In summary, the objective of
the Rotterdam Study was to investigate the determinants of chronic and
disabling cardiovascular, neurogeriatric, locomotor,
and ophthalmologic diseases. The baseline examination started in 1990
and continued until June 1993. The examinations consisted of a
home visit by trained interviewers and 2 follow-up visits for a
clinical examination at the research center. The study was approved by
the Medical Ethics Committee of Erasmus University, and written
informed consent was obtained from all participants.
Measurements
Blood Pressure
On 1 occasion, systolic and diastolic blood
pressures from the right upper arm were measured with a random-zero
sphygmomanometer twice with the patient in a sitting position. The mean
of the 2 blood pressure readings was used to determine blood pressure
levels. Hypertension was defined as a systolic blood pressure
of
160 mm Hg, a diastolic blood pressure of
95 mm Hg, the current use of blood pressurelowering drugs for
the indication of hypertension, or a combination. The use of medication
and type of medication were assessed during the home interview by a
research assistant. The participants subsequently showed all their
currently used medication at the research center, where a physician
determined the indication for which each medication had been
prescribed. In case of blood pressure levels below the cutoff points
and inconsistencies or missing values regarding indication, additional
information was used to classify subjects as hypertensive or
nonhypertensive. This additional information was obtained, first, from
the response to the question, "Have you ever been told by a doctor
that you have hypertension?" and, second, from the response to the
question, "Were you ever treated with drugs because of high blood
pressure?"
On the basis of their awareness, treatment status, and control of hypertension, hypertensives were classified into 4 subgroups: treated and controlled, treated and uncontrolled, untreated and aware, and untreated and unaware. In the hypertensives who were treated, a distinction was made between those for whom blood pressure was <160/95 mm Hg and thus controlled ("treated and controlled") and those for whom blood pressure was not controlled ("treated and uncontrolled"). Information on awareness was obtained on the basis of the response to the question, "Have you ever been told by a doctor that you have hypertension?" By definition, those who were treated were considered to be aware of having hypertension. Blood pressurelowering drugs were classified into 3 categories: diuretics, ß-blockers, and "other" antihypertensive medication.
Sociodemographic Factors
Information on education, occupation (eg, professionals, routine
nonmanual workers, small business owners, and manual workers), and
household income (in quartiles) as indicators of socioeconomic status
was obtained by trained interviewers during the home visit at the study
baseline (1990 to 1993). Similar results were observed for the
associations of hypertension with these different indicators. We report
here the results for the indicator "education" only, because the
number of missing values (4%) for this indicator was the lowest. The
participants were asked about their formal education, the number of
years of each type of education, and whether education had been
completed. From this information, the highest attained level of
education was defined, and this was classified into 3 categories: low
(eg, primary education), medium (eg, lower-level general education,
intermediate-level general education, and lower-level vocational
education), and high (eg, higher-level general education,
intermediate-level vocational education, higher-level vocational
education, and university). The other sociodemographic factors (ie,
"having a partner," health insurance status, and living situation)
were assessed during the same interview with a questionnaire. On the
basis of the question regarding partnership, subjects were categorized
into 2 groups: those currently with a partner and those without a
partner, including widowed and divorced persons. Health insurance was
dichotomized into health insurance via the Sickness Fund (for persons
below a certain income level) and private insurance (for persons above
this income level and civil servants). Living situation was divided
into living independently and living in a home for the
elderly.
Data Analysis
All analyses were performed with the SPSS package
and were performed separately for women and men. The prevalence of
hypertension was assessed on the basis of 5-year age groups. These
age-specific prevalence rates were weighted according to the age
distribution in the Netherlands in 1992 to estimate the
prevalence of hypertension for the total Dutch elderly
population. Frequencies of awareness, treatment, or control were
assessed on the basis of 10-year age groups. Mean blood pressure levels
according to 10-year age groups and by subgroups of hypertensives were
calculated with regression analysis. In addition, regression
analyses in which age was included as an ordinal variable
(1, 2, 3, and 4) were performed to test for trend.
Multivariate linear and logistic regression analyses were performed to determine the age-adjusted association between several sociodemographic factors and blood pressure levels, prevalence of hypertension, being unaware of having hypertension compared with being aware, being untreated compared with being treated, and having uncontrolled compared with having controlled hypertension. In addition, the relationship between these factors and the use of a certain type of medication was assessed with multivariate logistic regression analysis.
| Results |
|---|
|
|
|---|
|
Prevalence of Hypertension
Figure 1 shows the increasing
prevalence of hypertension with age for men and women. The overall
prevalence of hypertension, standardized to the total Dutch population,
was higher in women than in men (39% and 31%, respectively). For the
women, the prevalence of hypertension continuously increased with age,
from 22% in the youngest age group to 52% in those
85 years old.
For men, the prevalence rate increased with age until 80 years (from
22% to 39%).
|
Awareness, Treatment, and Control of Hypertension
Figure 2 shows the levels of
awareness, treatment, and control of hypertension for male and female
hypertensives by age. In total, 25% of the hypertensive men and 18%
of the hypertensive women were not aware of having hypertension. Of
those aware of having hypertension,
82% were treated. Furthermore,
70% of those treated were normotensive with treatment. Of all
hypertensives, only 46% had controlled hypertension. For both genders,
this proportion of controlled hypertensives decreased with age, whereas
the proportion of treated uncontrolled hypertensives increased with
age. For men, the proportion of persons aware of having hypertension
(treated and untreated) also decreased with age.
|
Blood Pressure
Table 2 shows the mean
systolic and diastolic blood pressure values for
the total population and for subgroups classified by awareness and
treatment status. In general, systolic blood pressure increased
and diastolic blood pressure decreased with age. Women
showed a stronger increase in systolic blood pressure with age
than did men. The decrease in diastolic blood pressure with
age was more marked among men than among women. Despite these
differences between men and women, mean systolic and
diastolic blood pressures did not considerably differ
between men and women. The mean systolic and
diastolic blood pressures of controlled hypertensives were
slightly higher than those of the normotensives.
|
Antihypertensive Drug Treatment
Table 3 shows the proportions of the
various blood pressurelowering drugs used by men and women in
monotherapy or combination therapy. Diuretics were more often
prescribed for older patients and for women. Furthermore, the use of
ß-blockers decreased with age. Other antihypertensive drugs, such as
calcium channel antagonists, were mainly prescribed for
male hypertensives aged 65 to 74 years and female hypertensives aged 75
to 84 years. The proportion of patients using other antihypertensive
drugs was higher in men than in women.
|
Note that blood pressurelowering drugs are also prescribed for indications other than hypertension (for the normotensives as well as for the hypertensives); for example, almost 13% of the normotensives were using blood pressurelowering drugs for an indication other than hypertension.
Differences by Socioeconomic and Demographic Factors
Table 4 shows the age-adjusted odds
ratios for hypertension and for being unaware, untreated, or
uncontrolled according to several sociodemographic factors.
Hypertension was slightly more frequent among the more-educated men,
less-educated women, and those not living in a home for the elderly. A
higher systolic blood pressure was observed among those not
living in a home for the elderly (12 and 6 mm Hg for women and
men, respectively).
|
Among male hypertensives, less-educated men, those living in a home for the elderly, and those without a partner tended to be less aware of having hypertension. Among female hypertensives, no clear sociodemographic differences in awareness were observed.
For those aware of having hypertension, men and women without a partner, men with private health insurance, and men living in a home for the elderly were less often treated. Finally, a lower proportion of treated persons living independently had controlled hypertension compared with those living in a home for the elderly.
The type of treatment also differed by these sociodemographic factors. ß-Blockers were less often prescribed for the less-educated persons, those with insurance via the Sickness Fund, men with a partner, and women without a partner (results not shown). Diuretics were less often prescribed for the less-educated women and women without a partner. Finally, other antihypertensive agents were more often prescribed for women without a partner and those living in a home for the elderly (results not shown).
| Discussion |
|---|
|
|
|---|
First, the potential of selective participation must be addressed.
Despite a high response rate, it is likely that our study population is
relatively healthy compared with the total Dutch population, because
older persons and those with health problems are less likely to
participate.10 11 Consequently, the true prevalence rate
of hypertension in Dutch persons
55 years old may be somewhat higher.
In addition, our study population includes relatively more older
persons than the total Dutch population in these age groups. This
latter problem was solved with calculation of the total prevalence rate
of hypertension on the basis of age-weighted prevalence rates.
Blood pressure was measured twice at 1 visit; this may lead to an overestimation of the prevalence of hypertension and to an underestimation of adequately controlled patients among those treated with antihypertensive medication.12 For this reason, we used a definition of hypertension based on rather conservative blood pressure levels and the use of blood pressurelowering medication. The relatively high blood pressure criteria limit the potential of misclassification of a diagnosis of hypertension because blood pressure levels were based on measurements obtained at a single occasion. The definition of normotension includes subjects with borderline isolated systolic hypertension to such an extent that systolic blood pressure was between 140 and 160 mm Hg. This applied to 20% of the men and women. A comparison of the prevalence of hypertension with that of other studies should be done with caution because of different cutoff points, number of measurements, or different measurement techniques.13 14 For example, if we had chosen lower cutoff points of blood pressure levels (eg, 140/90 mm Hg) instead of 160/95 mm Hg, the prevalence rates of hypertension would have been 52% and 58% for men and women, respectively. In our study, we did not include in the prevalence estimates persons with a normal blood pressure who are using blood pressurelowering drugs for other indications than hypertension. Results from this study indicate that blood pressurelowering drugs are frequently used for other indications, especially in an older population. In several other reports, however, users of blood pressurelowering drugs were not specified by indication.
The classification of hypertensives into "untreated and unaware," "untreated and aware," and "treated and uncontrolled" categories may be affected by the differences in cognitive performance in this elderly population. Persons with cognitive decline could be misclassified, because they are likely to have had more problems with answering the questions. Furthermore, it is likely that cognitive decline with age is more prevalent among those with a lower socioeconomic status,15 among older persons, and possibly even in those with clinically elevated blood pressure levels. The direction in which this misclassification has affected the results is unclear.
To classify socioeconomic status in this study, we used the indicator "education." Each indicator (eg, education, occupation, and income) represents another dimension of socioeconomic status. However, there is some overlap among the main indicators of socioeconomic status. This is confirmed by our findings (not shown) that other available indicators of socioeconomic status (eg, income and occupational level) in general showed the same trends.
The results of this study demonstrate that hypertension is more prevalent among elderly women than among men and that the prevalence increases with age. Although a comparison with other studies is difficult due to the problems mentioned earlier, our results do not substantially differ from those obtained from a recent overview of studies on the prevalence of hypertension in the Netherlands.13 Other studies among elderly subjects have similarly shown a higher prevalence of hypertension among women compared with men and an increase with age.6 14 16 17 18 Hormonal factors, postmenopausal weight gain, and a different risk profile might account for the higher age-specific prevalence rates of hypertension among women compared with men.16 Diastolic blood pressure levels off with age,17 19 and at older ages systolic blood pressure rises, resulting in a higher prevalence of isolated systolic blood pressure.16 Possibly, the decline in diastolic blood pressure reflects increased atherosclerosis in this aging population due to stiffening of the large arteries.20
Several studies have demonstrated a beneficial effect of treatment in older persons. Trials of patients older than 60 years have shown that antihypertensive drug therapy reduces the risk of stroke, cardiovascular diseases, heart failure, and death.3 4 5 6 7 21 Nevertheless, several studies, including ours, have shown that a considerable proportion of the hypertensives are not aware of having hypertension and that among those who are aware, a considerable proportion are not treated.17 22 23 24 25 26 The frequencies of awareness, however, appear to vary substantially, ranging from 23% in China to 97% in women in the United States.25 The percentage of aware of hypertensives in our study population, about 75%, is lower than that reported from most industrialized countries.17 Similar to most other studies, the women in our population have a better awareness than men.23 25 This finding suggests that general practitioners make different monitoring and treatment decisions according to gender or that health consciousness differs between genders.
In our male study population, unawareness of hypertension tended to increase with age. Several explanations for this increase with age can be considered. First, it is likely that physicians are still more hesitant to diagnose hypertension in elderly persons due to a lack of consensus on the cutoff points for hypertension and a possible awareness of white coat hypertension among elderly persons.27 Second, it is possible that the physician-patient communication differs with age. Third, cognitive function of the participants may have affected the awareness.
Approximately 66% of the hypertensives in our study population were treated, and for a majority of those (70%), this treatment was adequate with reference to our conservative criteria. A comparison of this proportion with the "rules of halves," which has been the dogma of the past (ie, only half of the hypertensives are detected, half of which are treated, of which only half achieve adequate blood pressure control), and other recent surveys among the elderly,19 28 suggests that there is an increasing tendency for medical treatment among the elderly and a better quality of control. However, a considerable proportion of the hypertensives are not treated or are treated ineffectively, especially at older ages. Indeed, in view of the recent data from the Hypertension Optimal Treatment (HOT) study, only 30% of the treated hypertensives in our study population reached the rather low targets defined in this trial. However, the public health impact of even a small decline can be substantial.
Until now, no single drug class is regarded as uniquely suitable as the first-line therapy for all elderly patients. For example, Messerli et al29 reported poor impact of the use of ß-blockers on blood pressure levels and the prevention of cardiovascular diseases exclusive of stroke in older hypertensives.29 Therefore, it is not possible to judge whether the persons are treated in an optimal way. The most appropriate choice of antihypertensive drug often depends on comparative adverse profiles, the presence of comorbidity,12 and the use of other medication.30 This might explain why treatment strategies differ according to gender and age. For example, diuretics were more often prescribed for patients at older ages and for women, and ß-blockers were less often prescribed for patients at older ages. In addition, our study showed that these medications are also frequently prescribed for other indications.
Several studies have reported an inverse association between socioeconomic status and hypertension or blood pressure level.31 32 Our findings among women are consistent with these studies. The positive association observed among men, however, is in contrast to these studies and is also in contrast to recent studies conducted in the Netherlands among younger persons.33 Nevertheless, the results in men are in line with Dutch studies carried out some decades ago.34 35 Hoeymans et al33 reported a change in the association between socioeconomic status and hypertension with time in the Netherlands. Our findings suggest, however, that this change may not occur within a generation but rather across the generations.
Our finding that health insurance status affects the treatment of male hypertensives suggests either that Dutch physicians distinguish between the type of insurance held by a patient or that men with private insurance use medical care in a different way compared with those without private insurance. Especially among men, "having a partner" may have a beneficial effect on the awareness and treatment of hypertension.36 Explanations for these associations with partnership require further investigation.
For 54% of the hypertensives, blood pressure levels were not controlled. To achieve a better control of hypertension among elderly persons, more attention should be given to the detection and subsequent treatment and control of hypertension. Subgroups of persons who require special care are men without a partner and men living in a home for the elderly.
In conclusion, the prevalence rate of hypertension is higher among older women and increases with age for both genders. A substantial proportion of hypertensive elderly persons are aware of and successfully treated for hypertension. However, a still considerable proportion of persons, which increases with age, do not have their hypertension well controlled. These hypertensives require more attention by medical practitioners to reduce the burden of cardiovascular diseases in the elderly.
| Acknowledgments |
|---|
Received March 3, 1999; first decision March 22, 1999; accepted October 14, 1999.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
S. L. Paul and A. G. Thrift Control of Hypertension 5 Years After Stroke in the North East Melbourne Stroke Incidence Study Hypertension, August 1, 2006; 48(2): 260 - 265. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Regidor, J. L Gutierrez-Fisac, J. R Banegas, V. Dominguez, and F. Rodriguez-Artalejo Association of adult socioeconomic position with hypertension in older people J. Epidemiol. Community Health, January 1, 2006; 60(1): 74 - 80. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. R. Biermasz, A. M. Pereira, J. W. A. Smit, J. A. Romijn, and F. Roelfsema Morbidity after Long-Term Remission for Acromegaly: Persisting Joint-Related Complaints Cause Reduced Quality of Life J. Clin. Endocrinol. Metab., May 1, 2005; 90(5): 2731 - 2739. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. W. A. Houben, W. J. Louwman, C. C. Tijssen, J. L. J. M. Teepen, C. M. van Duijn, and J. W. W. Coebergh Hypertension as a risk factor for glioma? Evidence from a population-based study of comorbidity in glioma patients Ann. Onc., August 1, 2004; 15(8): 1256 - 1260. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. de Gaudemaris, T. Lang, G. Chatellier, L. Larabi, V. Lauwers-Cances, A. Maitre, and E. Diene Socioeconomic Inequalities in Hypertension Prevalence and Care: The IHPAF Study Hypertension, June 1, 2002; 39(6): 1119 - 1125. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Hypertension Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2000 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |