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OlmeSartan and Calcium Antagonists Randomized (OSCAR) Study

This study has been completed.
Japan Heart Foundation
Information provided by:
OSCAR Study Identifier:
First received: August 22, 2005
Last updated: October 3, 2010
Last verified: October 2010
The purpose of this study is to investigate whether high-dose angiotensin II receptor blocker (ARB) monotherapy or combination therapy with ARB and calcium channel blockers is more effective in reducing the incidence of cardiovascular events in Japanese elderly high-risk hypertensive patients not adequately controlled by standard dose ARB alone.

Condition Intervention Phase
Cardiovascular Diseases
Drug: Olmesartan medoxomil
Drug: Calcium channel blockers (amlodipine, azelnidipine)
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Prevention
Official Title: The Study Comparing the Incidence of Cardiovascular Events Between High-dose ARB Monotherapy and Combination Therapy With ARB and Calcium Channel Blocker in Japanese Elderly Hypertensive Patients at High Cardiovascular Risk

Resource links provided by NLM:

Further study details as provided by OSCAR Study:

Primary Outcome Measures:
  • A composite of fatal and non-fatal cardiovascular events: Cerebrovascular events (cerebral infarction, cerebral hemorrhage, subarachnoid hemorrhage, stroke of undetermined etiology and transient ischemic attack) [ Time Frame: 36 Months ]
  • Coronary events (sudden death, myocardial infarction, angina pectoris, asymptomatic myocardial ischemia) [ Time Frame: 36 Months ]
  • Heart failure [ Time Frame: 36 Months ]
  • Vascular events (aortic aneurysm, aortic dissection, and arteriosclerotic diseases) [ Time Frame: 36 Months ]
  • Diabetic complications (nephropathy, retinopathy and neuropathy) [ Time Frame: 36 Months ]
  • Renal dysfunction (doubling of serum creatinine, end stage renal diseases) [ Time Frame: 36 Months ]
  • All cause mortality [ Time Frame: 36 Months ]

Secondary Outcome Measures:
  • Development of each cardiovascular event [ Time Frame: 36 Months ]
  • Blood pressure change (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean blood pressure [MBP]) at every observation point in the follow-up period [ Time Frame: 36 Months ]
  • Serious adverse events other than primary outcome events [ Time Frame: 36 Months ]

Estimated Enrollment: 1000
Study Start Date: August 2005
Study Completion Date: May 2010
Primary Completion Date: May 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1
High-dose ARB monotherapy
Drug: Olmesartan medoxomil
Olmesartan medoxomil 40mg/Day
Active Comparator: 2
Combination therapy of ARB with Calcium Channel Blocker
Drug: Calcium channel blockers (amlodipine, azelnidipine)
Olmesartan medoxomil 20mg/Day with Calcium channel blockers (amlodipine or azelnidipine)

Detailed Description:
Hypertension is one of the major risk factors of cardiovascular diseases. It is also important for elderly hypertensive patients to strictly reduce their blood pressures to prevent cardiovascular events. Although angiotensin II receptor blockers (ARBs) are increasingly used in antihypertensive treatment recently, few studies have been performed in Japan to assess the difference between high-dose ARB monotherapy and combination therapy of ARB with calcium channel blocker (CCB) in prevention of cardiovascular diseases for patients whose blood pressure is not well controlled by ARB monotherapy. OSCAR-study is a multicenter, active-controlled, 2-arm parallel group comparison, prospective randomized open blinded end-point (PROBE) design study. The dose administered is olmesartan medoxomil 20mg/day as ARB monotherapy in the 'Step 1' period. If the blood pressure is not adequately controlled and treatment is well tolerated then the dose is changed to olmesartan medoxomil 40mg/day in the high-dose ARB monotherapy group, or olmesartan medoxomil 20mg/day and a CCB in the combination therapy group in the 'Step 2' period. At least 500 patients will be enrolled in each group, and the follow-up duration will be 3 years. The primary objective is to compare the incidence of a composite of fatal and non-fatal cardiovascular events, and all cause mortality between the two treatment groups.

Ages Eligible for Study:   65 Years to 84 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Outpatients aged 65 years or older, and less than 85 years (at the time of informed consent), regardless of sex
  • Current antihypertensive treatment with monotherapy
  • SBP ≥ 140mmHg or DBP ≥ 90mmHg in a sitting position on two measurements on two clinic visits
  • At least one of the following risk factors:

    • Diabetes mellitus Type 2;
    • History of cerebral infarction, cerebral hemorrhage, subarachnoid hemorrhage, or transient ischemic attack (more than 6 months before giving informed consent);
    • Diagnosis of asymptomatic cerebrovascular disease;
    • History of myocardial infarction (more than 6 months before giving informed consent);
    • Diagnosis of angina pectoris or heart failure (New York Heart Association [NYHA] functional classification I or II);
    • Diagnosis of left ventricular hypertrophy (thickness of the wall of interventricular septum ≥ 12mm on echocardiography or Sv1+Rv5 ≥ 35mm on electrocardiography before informed consent);
    • Diagnosis of aortic aneurysm;
    • History of aortic dissection (more than 6 months before giving informed consent);
    • Diagnosis of arteriosclerotic peripheral arterial obstruction (Fontaine classification from 2 to 4);
    • Serum creatinine: 1.2-2.5mg/dL (male); 1.0-2.5mg/dL (female);
    • Proteinuria: ≥ +1 (or ≥ 0.3g/g・Cr. estimated from 24-hour urine collection or random urinary protein corrected by urine creatinine).

Exclusion Criteria:

  • Secondary hypertension or malignant hypertension
  • Heart failure (NYHA functional classification III or IV)
  • Required treatment for malignant tumor
  • Serious liver or renal dysfunction (serum creatinine > 2.5mg/dL or with dialysis treatment)
  • Not appropriate for change to the test drugs from current therapy for hypertension or coronary diseases (i.e. calcium channel blockers, β-blockers, thiazide diuretics, etc.)
  • History of serious adverse drug reactions to angiotensin II receptor blockers or calcium channel blockers
  • Patients with other serious reasons (i.e. illness, significant abnormalities, etc.) that investigators judge inappropriate for the study
  Contacts and Locations
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Please refer to this study by its identifier: NCT00134160

Department of Cardiovascular Medicine Graduate School of Medical Science Kumamoto University
1-1-1 Honjyo, Kumamoto-City, Kumamoto, Japan, 860-8556
OSCAR-Study Data Center
ShinjukuParkTower30FN, 3-7-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo, Japan, 163-1030
Sponsors and Collaborators
Japan Heart Foundation
Study Chair: Kikuo Arakawa, MD Emeritus Professor Fukuoka University, Fukuoka, Japan
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):

Responsible Party: Ogawa Hisao, Kumamoto University Graduate School of Medical Science Identifier: NCT00134160     History of Changes
Other Study ID Numbers: 15-April-2005
Study First Received: August 22, 2005
Last Updated: October 3, 2010

Keywords provided by OSCAR Study:
Cardiovascular Diseases
Angiotensin II Type 1 Receptor Blockers
Calcium Channel Blockers
Combination Drug Therapy
Diabetes Mellitus Type 2

Additional relevant MeSH terms:
Cardiovascular Diseases
Vascular Diseases
Calcium, Dietary
Olmesartan Medoxomil
Calcium Channel Blockers
Angiotensin II Type 1 Receptor Blockers
Bone Density Conservation Agents
Physiological Effects of Drugs
Antihypertensive Agents
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Vasodilator Agents
Angiotensin Receptor Antagonists processed this record on April 26, 2017