Prevalence, awareness, treatment and control of hypertension in the elderly: results from a population survey

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1 (2000) 14, Macmillan Publishers Ltd All rights reserved /00 $ ORIGINAL ARTICLE Prevalence, awareness, treatment and control of hypertension in the elderly: results from a population survey M Prencipe 1, AR Casini 1, M Santini 1, C Ferretti 1, N Scaldaferri 1 and F Culasso 2 1 Department of Neurological Sciences and 2 Department of Experimental Medicine, La Sapienza University, Rome, Italy Prevalence, awareness, treatment and control of hypertension were assessed in 1032 (90%) of 1147 elderly ( 65 years) inhabitants of three Italian villages. Blood pressure (BP) was measured at home on two separate occasions following a standardised protocol. Persons taking antihypertensive drugs or with BP values 140/90 mm Hg were considered as affected by hypertension. Prevalence of hypertension was 64.8%, with higher rates in women than men, and in those aged than in those aged Diabetes, strokes and hypercholesterolaemia were more frequent in hypertensive than normotensive people, whereas cardiac diseases, overweight and smoking did not differ significantly between hypertensive and normotensive people. Of the 669 hypertensive patients, 439 (65.6%) were aware of their hypertension, 398 (59.5%) were being treated, and 70 (10.5%) had their hypertension con- trolled. Of the 230 unaware patients, 201 (87.4%) had had their BP measured in the previous year. Of these, 174 (86.6%) had stage 1 hypertension, while 27 had stage 2 hypertension with SBP values 170 mm Hg. Overall, the patients with stage 1 hypertension accounted for 68.3% of the untreated and 50.5% of the treated patients. The use of a single drug was more frequent in patients with controlled (97.1%) or stage 1 (97.0%) than with stages 2 3 (18.9%) hypertension. The drugs prescribed most were angiotensin-converting enzyme (ACE) inhibitors (45%), followed by diuretics (43%). As our findings suggest that BP values can be effectively reduced by treating or increasing drug treatment in stage 1 hypertensive patients, data on safety and effectiveness of this policy are urgently needed. (2000) 14, Keywords: elderly; prevalence; awareness; treatment Introduction Although hypertension was once considered as a benign manifestation of aging, we now know that treatment of hypertension in elderly people reduces the risk of both stroke and major cardiovascular events. 1 4 However, observational studies have shown that awareness, treatment and control of hypertension could be improved, especially in elderly people. 5 8 Furthermore, the recent recommendations to treat all 9 or part 10,11 of elderly patients with stage 1 hypertension might further increase the gap between the proposed guidelines and actual trends in the management of hypertension. Therefore, data on awareness, treatment and control of hypertension in elderly populations help to understand the extent of this problem. Unfortunately, only few population studies have included people aged 65 or over and, moreover, data on stage 1 hyperten- Correspondence: Prof M Prencipe, Dipartimento di Scienze Neurologiche, Università di Roma La Sapienza, Box No 41, Viale dell Università 30, Roma, Italy prencipe uniromal.it Received 2 March 2000; revised 17 May 2000; accepted 28 June 2000 sion are often lacking because many studies used the 160/90 mm Hg threshold for hypertension. In 1992, we started a door-to-door two-phase survey to assess the prevalence of dementia, vascular diseases and disability in a rural population aged 65 or over. 12,13 In the present study, we report data on the prevalence, awareness, treatment and control of hypertension in this elderly population. Subjects and methods We considered eligible all the inhabitants aged 65 years, living in three rural villages near the town of L Aquila (central Italy) on 1 March All eligible inhabitants who gave their informed consent were examined at home following a door-to-door twophase procedure. 12 Before the start of the survey, the four lay interviewers and the four neurologists were trained in the scheduled procedures. Blood pressure (BP) was measured at home in both phases following a standardised protocol. The time interval between the first and the second set of BP evaluations ranged from 6 to 14 days. On each occasion BP was measured in the same arm, at the same time of day, after a rest of 5 min, with the participant in sitting position, using a standard mercury sphygmomanometer with

2 826 a cuff of appropriate size. Readings were based on the first and fifth Korotkoff sounds for systolic blood pressure (SBP) and diastolic blood pressure (DBP) respectively. BP readings were recorded to within the nearest 2 mm Hg. The protocol for BP evaluation required three BP readings obtained at 2-min intervals, and we used the average of the six BP readings obtained on the two occasions. We considered as hypertensive the persons with SBP values 140 mm Hg, DBP values 90 mm Hg or taking antihypertensive drugs regularly. Hypertensive patients were classified as affected by stage 1 (SBP of mm Hg or DBP of mm Hg) or stages 2 3 hypertension (SBP 160 mm Hg or DBP 100 mm Hg). 9 Stages 2 and 3 were collapsed because very few patients had stage 3 hypertension. Treated patients with BP values 140/90 mm Hg were considered as controlled. Patients with SBP values 140 mm Hg and DBP values 90 mm Hg were considered as affected by isolated systolic hypertension (ISH). Hypertensive patients were classified as either aware or unaware of their hypertension. The aware patients were further classified as treated or untreated. We considered as aware those hypertensive patients who answered yes to the question has a doctor ever told you that your BP values are too high or that you have hypertension? Hypertensive patients who did not know their BP values or who answered that their BP was normal for their age or high but normal were classified as unaware. In addition to BP measurements, the study protocol included a structured interview with participants and their proxies, followed by a standardised physical examination. As previously reported, 13 each participant underwent blood analyses and an electrocardiogram. Diabetes mellitus was defined as chronic hyperglycaemia (fasting blood glucose 7.8 mmol/l) requiring diet, oral medication or insulin treatment. Hypercholesterolaemia was defined as fasting blood total cholesterol level 6.2 mmol/l. Cardiac diseases were diagnosed on the basis of history, clinical examination and electrocardiographic findings. Persons with a positive history for stroke were considered as stroke patients only when the event consisted of a sudden neurological deficit lasting longer than 24 h with no apparent cause other than that of vascular origin. 14 We defined as smokers those persons who were smoking daily at the time of the survey, and considered as overweight those with a body mass index (BMI) 25 kg/m 2. We calculated age- and sex-specific prevalence rates (cases per 100 participants) for hypertension. Participants were stratified in three age groups: 65 74, and years. This last group included two persons aged 95 and one person aged 96. The 95% confidence intervals (CIs) of the percentages were calculated by using the approximated formula based on normal distribution. 15 Interval variables are expressed as mean ± standard deviation (s.d.), with unpaired Student s t-test or Mann-Whitney U test being used to compare mean values. The comparison for nominal variables was performed by 2 test. A probability value of P 0.05 was considered as evidence of statistical significance. To evaluate a possible independent effect of age (1-year increments) and sex on being untreated for hypertension, we calculated the odds ratios (ORs) and the 95% CI by means of multiple logistic regression analysis. Results A total of 1032 (90%) of the 1147 inhabitants aged 65 completed the study protocol. Of the remaining 115 inhabitants, 60 refused to be interviewed, 29 moved elsewhere or were not found, and 26 died before the evaluation. Participants and drop-outs did not differ significantly with regard to age (mean age 74.2 and 75.5, respectively; Mann-Whitney U test, P = 0.06) and proportion of women (56.7% and 60.9%, respectively; 2 test, P = 0.45). Mean BP values of the 1032 participants were ± 17.2 s.d. mm Hg for SBP and 81.6 ± 7.6 s.d. mm Hg for DBP. The hypertensive patients accounted for 669 (64.8%) of the 1032 participants. As shown in Table 1, the prevalence of hypertension was significantly higher in women than men (P 0.001), and in those aged than in those aged (P = 0.001). As shown in Table 2, diabetes, hypercholesterolaemia and stroke were more frequent in hypertensive than normotensive people. Although cardiac diseases and being overweight were more frequent in hypertensive than normotensive people, the difference was not statistically significant. The proportion of smokers was much higher in men than women (67.3% and 3.7% respectively; P 0.001), without significant differences between normotensive and hypertensive people in either sex. Of the 1032 participants, 956 (92.6%) reported that their BP had been measured at least once in the previous year. Of these, 325 were normotensive (equivalent to 89.5% of the 363 normotensive persons), while 631 were hypertensive (equivalent to 94.3% of the 669 hypertensive patients, P 0.01). In spite of this high rate of BP detection, only 439 (65.6%) of the 669 hypertensive patients were aware of their hypertension. Of the remaining 230 unaware patients, 201 (87.4%) had had their BP measured in the previous year. Of these, 174 (86.6%) had stage 1 hypertension and the remaining 27 (13.4%) had ISH with SBP values 170 mm Hg. Of the 669 hypertensive patients, 398 (59.5%) were treated and 271 (40.5%) were untreated. As shown in Figure 1, the proportion of untreated patients was higher in men than women, and rose with increasing age. Although the proportion of untreated patients did not differ significantly between the three age groups, the mean age was significantly higher in untreated than treated patients (75.6 ± 6.6 s.d. and 74.3 ± 6.1 s.d., respectively; Mann-Whitney U test, P = 0.03). At the multiple logistic regression analysis, the OR of being untreated was 1.6 (95%, CI, ) for men and 1.03 (95% CI, ) for age (1-year increments). Of the 271 untreated patients, 41 (6.1% of all hypertensive patients) were aware of their hypertension. They comprised 29 patients (4.3% of all hyper-

3 Table 1 Prevalence of hypertension by age and sex 827 Age (years) Men Women All n % 95% CI n % 95% CI n % 95% CI / / / / / / / / / All 252/ / / Table 2 Risk factors and associated diseases in normotensive and hypertensive people All participants Normotensive Hypertensive 2 (n = 1032) (n = 363) (n = 669) test n % n % n % P Diabetes Hypercholesterolaemia Stroke Cardiac diseases Overweight Table 3 BP stages in untreated and treated hypertensive patients Untreated Treated All n % n % n % Controlled a Stage 1 b Stages 2 3 c All patients a Controlled = treated hypertensive patients with SBP 140 mm Hg and DBP 90 mm Hg. b Stage 1 = SBP of mm Hg or DBP of mm Hg. c Stage 2 3 = SBP 160 mm Hg or DBP 100 mm Hg. Figure 1 Bar graphs show the percentages of untreated hypertensive patients according to gender and age distribution. P values are calculated by 2 test. tensive patients) who refused to be treated, and 12 patients (1.8% of all hypertensive patients) who withdrew the antihypertensive treatment because of side effects. As shown in Table 3, 86 (31.7%) of the 271 untreated patients had stage 2 3 hypertension. They included all the 41 aware patients and 45 (19.6%) of the 230 unaware patients. The remaining 185 unaware patients had stage 1 hypertension. These 185 patients accounted for 27.7% of all hypertensive patients and for 17.9% of all participants. The prevalence of stage 1 untreated hypertensive patients was 16.8% in men and 18.8% in women (P = 0.45), and 14.9%, 21.1% and 26.5% in those aged 65 74, 75 84, and respectively (P = 0.01). Treated and untreated hypertensive patients had similar SBP values (153.2 ± 11.4 s.d. mm Hg and ± 16.0 mm Hg respectively; Student s t-test, P = 0.58) and similar DBP values (84.5 ± 6.2 mm Hg and 84.4 ± 7.3 mm Hg respectively; Student s t-test, P = 0.84). Furthermore, the patients affected by stages 2 3 hypertension accounted for 213 (31.8%) of the 669 hypertensive patients, with similar proportions in treated and untreated patients (Table 3). ISH was observed in 419 (62.6%) of the 669 hypertensive patients. The proportion of patients with ISH was higher in those with stage 1 than stages 2 3 hypertension in both the untreated (77.8% and 61.6%, respectively; P 0.01) and treated patients (80.6% and 47.2%, respectively; P 0.001). Of the 398 treated patients, 70 (17.6%) had their hypertension controlled, 201 (50.5%) had stage 1 hypertension and 127 (31.9%) had stages 2 3 hypertension (Table 3). As shown in Table 4, 287 (72.1%) of the 398 treated patients were taking a single drug. The most frequently used drugs were ACE inhibitors in those taking one drug, and diuretics in those taking two or more drugs. The patients being treated with a single drug accounted for 24 (18.9%) of the 127 patients with stages 2 3 hypertension, 195

4 828 Table 4 Proportion (%) of hypertensive patients treated with one or more drugs One drug Two or more All treated (n = 287) drugs (n = 398) (n = 111) ACE inhibitors Diuretics Calcium antagonists Beta-blockers (97.0%) of the 201 patients with stage 1 hypertension, and 68 (97.1%) of the 70 patients whose hypertension was controlled (P 0.001). Of the 111 patients taking more than one drug, 68 (61.2%) were taking diuretics and angiotensin-converting enzyme (ACE) inhibitors, 12 (10.8%) diuretics and betablocking agents, 10 (9.0%) calcium antagonists and ACE inhibitors, nine (8.1%) diuretics and calcium antagonists, and the remaining 12 (10.8%) were taking three drugs. Discussion The prevalence of hypertension in this elderly rural population was 64.8%. The high response rate (90%) achieved in our study should have limited the effects of a possible selection bias. In accordance with previous reports, 16,17 our prevalence rates were higher in women than men and in those aged than in those aged In the age group, the prevalence of hypertension was 59.7%, a figure slightly higher than the 54.3% observed in people of similar age by the NHANES III study. 18 In other population studies on people aged 65 or over, in which the threshold for hypertension was 140/90 mm Hg, prevalence rates ranged from 51.4% to 77.5% Differences in case ascertainment procedures and in the protocol for BP evaluation have probably contributed to cause these wide variations in prevalence rates. In order to conform our data to those of the NHANES III study, 18 we used the average of six BP measurements obtained at home on two separate occasions. However, in a group of people examined for the standardisation of the protocol for BP measurements, we noticed that BP values obtained on the second occasion were often lower than those observed on the first. Furthermore, the BP values obtained in the second and third measurements were sometimes lower than those in the first. Therefore, if we had used a different protocol, both our prevalence estimates and the proportions of treated patients with stage 1 or stages 2 3 might have been slightly lower. This problem deserves consideration when therapeutic decisions are involved. In our study, 89.5% of normotensive and 94.3% of hypertensive patients reported they had had their BP measured in the previous year. These proportions are higher than the 73% observed in a Greek rural population aged 18 or over. 22 Our higher rates of BP monitoring are probably due to the increased attention that elderly people pay to their health and to the characteristics of the public health care system presently available in Italy. In spite of these high rates of BP monitoring, only 65.6% of our hypertensive patients were aware of their hypertension. Interestingly, of the 87.4% unaware patients who had had their BP measured in the previous year, 86.6% had stage 1 hypertension. Furthermore, the remaining 13.4% suffered from ISH with SBP 170 mm Hg. Therefore, we think that these patients were unaware of their hypertension because their doctors decided not to treat them and consequently did not inform them about their hypertension. This explanation of our finding is consistent with previous reports indicating that doctors were not inclined to treat elderly people with stage 1 hypertension or with stages 2 3 ISH. 3 5 The recently reported positive effects of antihypertensive treatment on elderly patients with stages 2 3 ISH will probably induce physicians to treat this type of patient in the future. By contrast, the decision to treat elderly people with stage 1 hypertension is less clear-cut because direct evidence of the benefit of antihypertensive therapy in such patients is still lacking. 11 As stage 1 hypertensive patients accounted for 68.3% of our untreated hypertensive patients, for 27.7% of all hypertensive patients and for 17.9% of all elderly people, we think that more information on the effect of therapy in these patients is urgently needed. Notwithstanding this lack of data, appropriate lifestyle modifications are surely useful in decreasing BP values and in reducing cardiovascular risks. 26,27 Unfortunately, we found that nearly twothirds of men were smokers and half of the participants were overweight. Furthermore, the proportion of people with these modifiable risk factors did not differ between normotensive and hypertensive patients. Although we do not have reliable data on sodium and alcohol intake in this elderly population, our findings on being overweight and smoking suggest that this population is not sufficiently aware of the positive effects attainable by appropriate lifestyle modifications. In our study, the proportion of hypertensive patients taking antihypertensive drugs was 59.5%, a figure slightly higher than the 53 54% observed in other elderly populations ,28 In spite of the higher proportion of treated patients, the mean BP values of our treated patients were higher than those observed in other studies. 20,28 30 Furthermore, 31.9% of our treated patients still had stage 2 3 hypertension, 50.5% had stage 1 hypertension, and only 17.6% had their hypertension controlled. This last figure is far lower than the 42% observed in the NHANES III study. 31 Interestingly, the proportion of hypertensive patients treated with a single drug was 72% in our study, 53% in a German elderly population, 16 and 45% in a cohort of over 6000 patients followed by six Veteran Administration Clinics. 30 Furthermore, our patients treated with a single drug accounted for 18.9% of those with stage 2 3 hypertension and 97.0% of those with stage 1 hypertension. Therefore, a more aggressive drug regimen in the patients with stage 1 hypertension would probably have increased the proportion of hypertensive patients who had their hypertension controlled.

5 Although some studies suggest that this should be a priority, especially in diabetic patients, 32,33 the recently reported positive association between stroke risk and low DBP in elderly patients taking antihypertensive drugs suggests that a prudent strategy in the treatment of elderly patients is advisable. 34 Furthermore, a more aggressive drug regimen would probably increase the proportion of treatment withdrawals, which amounted to only 1.8% in our hypertensive patients. Lastly, the drugs most frequently used in this elderly population were ACE inhibitors (45%), followed by diuretics (43%) and calcium-antagonists (24%). The fact that these findings are consistent with other studies points to a rapid increase in the prescription of ACE inhibitors and calcium-antagonists, and a corresponding decrease in the prescription of diuretics Old age, as well as comorbidity frequently present in elderly patients, have probably contributed to cause this change in prescription attitudes. 38,39 Conclusions Despite the high rates of BP values monitoring and the frequent prescription of new antihypertensive drugs, a consistent proportion of this elderly population has excessively high BP values. Our findings suggest that this state of affairs could be improved principally by treating or increasing drug treatment in patients with stage 1 hypertension. The high number of patients involved and the frequent BP measurements required to avoid incorrect decisions markedly increases the workload of nurses and doctors. Furthermore, the start of therapy in untreated patients and the prescription of new or more drugs in patients already being treated have social and psychological effects that cannot be overlooked. Therefore, we think that data on the safety and efficacy of this more aggressive treatment in elderly are urgently needed. Acknowledgements We wish to thank all the general practitioners and lay interviewers for their contributions to the data collection, and Lewis Baker for his assistance in preparing the manuscript. This study was supported by a grant from National Research Council (CNR PF40). References 1 Insua JT et al. Drug treatment of hypertension in the elderly: a meta-analysis. Ann Intern Med 1994; 121: Lever AF, Ramsey LE. Treatment of hypertension in the elderly. J Hypertens 1995; 13: Staessen JA, Wang JG, Thijs L, Fagard R. Overview of the outcome trials in older patients with isolated systolic hypertension. J Hum Hypertens 1999; 13: Gueyffier F et al. 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