Combination of OLMesartan and CCB or Low Dose Diuretics in High Risk Elderly Hypertensive Patients Study (COLM-Study)

Inclusion Criteria: * Outpatients aged 65 years or older, and less than 85 years (at the time of informed consent), regardless of sex * Systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥90 mmHg in a sitting position on two consecutive measurements at clinic during use of 1 or more antihypertensive medications. * Systolic blood pressure (SBP) ≥160 mmHg or diastolic blood pressure (DBP) ≥100 mmHg in a sitting position on two consecutive measurements at clinic without antihypertensive medication. * Require at least one of the following medical history or risk factors * Medical history * Cerebrovascular accident: cerebral infarction, brain hemorrhage, subarachnoid hemorrhage（6 months or more prior to registration） * Myocardial infarction, coronary revascularization (PCI or CABG) （6 months or more prior to registration） * Angina pectoris (except for the patients having history of hospitalization within 6 months prior to registration) * Risk factors * Male * Current diabetes mellitus, fasting glucose ≥ 110mg/dL or postprandial glucose ≥ 140mg/dl * Hypercholesterolemia (Total cholesterol ≥ 260mg/dL) * Low HDL cholesterolemia (HDL-C \<40mg/dL) * Microalbuminuria (albumin/cr ≥ 30mg/gCr) or proteinuria (protein ≥ 1＋) * Left ventricular hypertrophy (ST-T change in the ECG and SV1＋RV5 ≥ 35mm, or left ventricular mass index: male ≥ 125 g/m2, female ≥ 110 g/m2) Exclusion Criteria: * Secondary hypertension or malignant hypertension * History of cerebrovascular accident (including TIA) or myocardial infarction within 6 months before registration * Percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) done within 6 months before registration or scheduled * History of hospitalization for angina pectoris or heart failure within 6 months before registration * Severe heart failure (New York Heart Association \[NYHA\] functional class III or more severe) * Complications of atrial fibrillation, atrial flutter or severe arrhythmia * Severe hepatic or renal dysfunction (including current treatment of dialysis or renal dysfunction with serum creatinine ≥ 2.0mg/dL) * Not appropriate for change to the study drugs from current therapy for concurrent disease including coronary diseases (i.e. calcium channel blockers, diuretics, etc) * History of serious side effect from study drugs (AT1 subtype angiotensin II receptor antagonist, calcium channel blocker, diuretic) * Life threatening condition (malignant tumor, etc) * Not suited to be study subject judged by a study physician