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J Am Coll Cardiol, 2004; 44:1175-1180, doi:10.1016/j.jacc.2004.06.034 © 2004 by the American College of Cardiology Foundation |

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* Hypertension and Cardiovascular Research, Veterans Administration Medical Center, Washington, DC, USA
First Department of Internal Medicine St. Emeric Teaching Hospital, Budapest, Hungary
Department of Public Health and Caring Sciences, Sections of Geriatrics, Clinical Hypertension Research and Family Medicine, University of Uppsala, Uppsala, Sweden
|| Departments of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam, the Netherlands
Clinical Science, Medicine and Biostatistics, AstraZeneca R&D, Mölndal, Sweden
¶ Institute of Clinical Neurosciences, Neuropsychiatric Epidemiology Unit, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden
# Department of Internal Medicine, Starnberg Hospital, Ludwig Maximilian University Munich, Starnberg, Germany
** Centro di Fisiologia Clinica e Ipertensione, University of Milan and Istituto Auxologico Italiano, Milan, Italy
Manuscript received February 15, 2004; revised manuscript received June 3, 2004, accepted June 7, 2004.
* Reprint requests and correspondence: Dr. Vasilios Papademetriou, Director, Hypertension & Cardiovascular Research, Co-Director, Cardiac Catheterization Laboratory, Veterans Administration Medical Center, 50 Irving Street NW 151E, Washington, DC 20422 (Email: papavip{at}aol.com).
| Abstract |
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BACKGROUND: Isolated systolic hypertension is the predominant form of hypertension in the elderly, and stroke is the most common cardiovascular (CV) complication.
METHODS: In the Study on Cognition and Prognosis in the Elderly (SCOPE), 4,964 patients age 70 to 89 years were randomly assigned to double-blind candesartan or placebo with open-label antihypertensive therapy (mostly thiazide diuretics) added as needed to control blood pressure. Of the 4,964 patients, 1,518 had ISH (systolic blood pressure >160 mm Hg and diastolic blood pressure <90 mm Hg). The present study is a predefined subgroup analysis of outcome results in the ISH patients.
RESULTS: Of the ISH patients, 754 were randomized to the candesartan group and 764 to the control group. Over the study period, blood pressure was reduced by 22/6 mm Hg in the candesartan group and by 20/5 mm Hg in the control group (difference between treatments 2/1 mm Hg; p = 0.101 and 0.064). A total of 20 fatal/non-fatal strokes occurred in the candesartan group (7.2/1,000 patient-years) and 35 in the control group (12.5/1,000 patient-years); relative risk (RR) was 0.58 (95% confidence interval 0.33 to 1.00), that is, a RR reduction of 42% (p = 0.050 unadjusted, p = 0.049 adjusted for baseline risk). There were no marked or statistically significant differences between the treatment groups in other CV end points or all-cause mortality.
CONCLUSIONS: In elderly patients with ISH, antihypertensive treatment based on the ARB candesartan resulted in a significant 42% RR reduction in stroke in comparison with other antihypertensive treatment, despite little difference in blood pressure reduction.
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Although the benefit of treating ISH in older hypertensive populations has been clearly established (3,4), it is not clear whether specific drug therapies confer additional benefit beyond blood pressure control. The only publication, so far, is based on an analysis of patients with ISH and electrocardiographic evidence of left ventricular hypertrophy, participating in the Losartan Intervention For Endpoint reduction (LIFE) study (6). This LIFE substudy demonstrated substantial reduction in CV mortality, stroke, and new-onset diabetes mellitus with the angiotensin II type 1 (AT1) receptor blocker (ARB) losartan-based treatment as compared with the beta receptor blocker atenolol-based treatment in patients with ISH, despite similar blood pressure reduction.
The Study on Cognition and Prognosis in the Elderly (SCOPE) was designed as the first large-scale clinical trial to determine the effects of an ARB on CV and cognitive outcomes in elderly patients with mild to moderate hypertension (7). The SCOPE was initially conceived as a comparison of candesartan with placebo. However, treatment guidelines changed during the recruitment phase of the study, and the protocol was amended, for ethical reasons, to recommend the addition of open-label antihypertensive therapy in patients whose blood pressure remained too high. As a result, a large proportion of patients, especially in the "placebo" group, received additional antihypertensive medication, and the trial became a comparison of a candesartan-based regimen with a regimen not containing candesartan. Indeed, 84% of the patients in the control group received active antihypertensive medication. The primary results from the SCOPE have been published (8). The mean blood pressure reduction was pronounced in both the candesartan group (21.7/10.8 mm Hg) and the control group (18.5/9.2 mm Hg, mean difference between treatments: 3.2/1.6 mm Hg). Non-fatal stroke was 27.8% lower in patients treated with candesartan compared with those in the control group (p = 0.04), and all stroke was reduced by 23.6% (p = 0.06). Other CV events were not significantly different between groups.
The present study is a predefined subgroup analysis of outcome results in the SCOPE patients with ISH, defined as systolic blood pressure (SBP)
160 mm Hg and diastolic blood pressure (DBP) <90 mm Hg.
| Patients and methods |
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The study consisted of an open run-in period (one to three months) followed by a double-blind treatment period of three to five years. Patients were randomized (1:1) by a central, computer-generated randomization schedule to receive either candesartan 8 mg or a matching placebo tablet once daily in the morning. Study medication was doubled to two tablets once daily if, at any consecutive visits, the patient met any of the following criteria: SBP >160 mm Hg, decrease in SBP of <10 mm Hg compared with the randomization visit, or DBP above 85 mm Hg. Patients with SBP
160 mm Hg or DBP
90 mm Hg after receiving two tablets of study medication could receive additional antihypertensive medication. In accordance with the protocol, HCTZ 12.5 mg daily was the preferred medication to be added to study treatment. Subsequently, any other antihypertensive medication could be added, excluding ARBs or angiotensin-converting enzyme inhibitors.
The primary end point of the SCOPE was a first major CV event (CV death, non-fatal myocardial infarction, or non-fatal stroke). A number of secondary end points were also prespecified. These included cognitive function as measured by the MMSE, dementia, total mortality, CV mortality, fatal and non-fatal myocardial infarction (separate and combined), fatal and non-fatal stroke (separate and combined), new-onset diabetes mellitus, and discontinuation of study drug as a result of adverse events.
The study was conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. The study protocol and patient consent forms were approved by the appropriate ethics committee at each institution that participated in the study. Patients were recruited into the study between March 1997 and January 1999, and the follow-up phase ended in March 2002. A total of 527 centers in 15 countries, mainly in Europe, participated in the study.
Statistical methods. The analysis was conducted according to the intention to treat and last value carried forward principles. Differences between the treatment groups in "time to event" were analyzed with a log-rank test and in a Cox regression model. The p values for the interaction treatment by subgroups (ISH/non-ISH) were calculated in a Cox regression analysis. Adjustment for baseline CV risk according to the criteria given in the 1999 World Health Organization-International Society of Hypertension guidelines (9) was done in a Cox regression model to account for possible differences in risk at baseline. Differences in proportions of patients with an event were analyzed using the chi-square test. The continuous variables, such as change in blood pressure or MMSE score from baseline, were symmetrically distributed and tested in an analysis of covariance model, with prespecified factors adjusting for country and baseline value. Two-sided p values and 95% confidence intervals (CI) are used in this report. Data are shown as mean values with standard deviation where appropriate.
| Results |
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Treatment was generally well tolerated in both groups. A similar proportion of patients in the candesartan group and the control group discontinued treatment because of adverse events (candesartan 17.3%, control 17.6%), whether considered related to the study drug or not. The most common adverse events reported were dizziness/vertigo, accident/injury, back pain, and bronchitis, and they occurred in similar proportions of patients in both treatment groups.
| Discussion |
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No statistically significant differences between the treatment groups were noted in any other individual health outcome measure, although trends toward benefit with candesartan-based treatment were noted for several end points, for example, major CV events, all myocardial infarction (fatal + non-fatal), all-cause death, and new-onset diabetes mellitus. The observed risk reduction in stroke with candesartan-based therapy is important not only because stroke is a disabling and much feared complication of hypertension, it is also the predominant complication in elderly patients with hypertension. As noted in recent trials (5) and also observed in the SCOPE, strokes have surpassed coronary events in treated older patients with hypertension.
The estimated mean RR reduction in all stroke with candesartan was greater in patients with ISH (42%) than in the entire SCOPE population (24%), or in the non-ISH population (16%). However, this does not preclude similar benefit in ISH and non-ISH patients, because the 95% CI were wide (because of relatively few events) and overlapping, and the interaction test (treatment by ISH/non-ISH) was non-significant (p > 0.20).
There was no significant difference between the treatment groups with respect to cognitive function as measured by MMSE or dementia in patients with ISH. This was similar to the overall study results (8). There was a marked reduction, 28%, in new-onset diabetes in the candesartan group compared with the control group in this subset of patients, although not statistically significant. These observations are consistent with the results of the main analysis, including the entire SCOPE study population, and possible explanations have been discussed (8).
The stroke results in patients with ISH in the SCOPE are in line with the results reported by the LIFE investigators in a similar analysis of patients with ISH (6). Patients in LIFE with ISH, treated with losartan experienced 40% fewer strokes, 46% lower CV mortality, and 38% lower new-onset diabetes as compared with those treated with atenolol. Although the two studies have similarities, they also differ in several important aspects: Patients in the LIFE trial were selected to be hypertensive with left ventricular hypertrophy, whereas patients in the SCOPE were of high age, both known strong independent markers of increased risk for CV events. However, the rate of stroke per 1,000 patient-years was 10.6 for losartan and 18.9 for atenolol in the LIFE trial and 6.1 for candesartan and 10.0 for control in the SCOPE. The comparator in the LIFE trial was a beta-blocker, whereas in the SCOPE it was mostly a diuretic.
There were fewer events in the SCOPE than originally expected, probably at least partly because of extensive antihypertensive treatment in the control group. This reduces the power of the statistical analyses and is a limitation of the trial, especially when subgroups of patients are considered. For example, there were only a total of 55 strokes in the ISH patients.
It is important to note that the SCOPE was conducted in elderly patients, a population in which ISH is the dominant subtype of hypertension. The median age of the ISH participants in the SCOPE was 77.3 years, and nearly 30% of the patients were 80 years old or above. In comparison, the study populations in the SHEP and the Syst-Eur trials were younger (mean age, 70 to 72 years) (3,4).
Blood pressure reduction was slightly better (2.0/1.2 mm Hg) with the candesartan-based regimen compared with the control regimen, but the difference was not statistically significant. It is possible that these relatively small differences in blood pressure could account for part of the observed clinical benefit on stroke. In the Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial (ALLHAT), use of the diuretic chlorthalidone lowered SBP by only 2 mm Hg more than the angiotensin-converting enzyme inhibitor lisinopril, yet resulted in a 15% lower risk of stroke (p = 0.02) (10). Other studies have likewise demonstrated the impact of incremental reductions in blood pressure on stroke. Reducing DBP by 2 mm Hg in previously untreated hypertensive patients has been estimated to prevent 15% of strokes (11), and similar results have been estimated for small reductions in SBP (12). A recent meta-analysis (13) of data from close to one million adults from 61 prospective, observational studies showed the impact of small changes in SBP or DBP. The risk of stroke was incremental and continuous from SBP of 115 mm Hg and above. These observations indicate that the small difference in blood pressure between the treatment groups in the SCOPE could account for a difference in stroke of approximately 15%.
Thus, it is possible that the favorable effect on stroke in the ARB-treated groups in both the SCOPE and LIFE trials is related to AT1-receptor blockade (and/or AT2-receptor activation) and not just to blood pressure lowering. The hypothesis of cerebroprotection by AT2-receptor activation has recently been emphasized (14). It is supported by several animal studies (1521) that indicate neuroprotective effects of specific AT1-receptor blockade at concentrations not affecting blood pressure. Similarly, results from clinical trials indicate that specific AT1-receptor blockade may have value in the secondary prevention of stroke, which cannot be fully explained by blood pressure reduction (22).
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| Footnotes |
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| References |
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