Obstructive sleep apnea (OSA) is a highly prevalent chronic sleep disorder that affects 3% to 7% in middle aged individuals and increases with age. OSA has been identified as the most common secondary cause associated with resistant hypertension. There is evidence that compared with older patients, the risk of hypertension in OSA patients may be particularly pronounced in younger adult ones (less than 50 years).

Traditionally, cardiovascular risk stratification in hypertensive patients was based on the average blood pressure (BP) measured in the clinic. Accumulated data has shown that target-organ damage is related not only to 24-h mean intra-arterial BP, but also to BP variability (BPV) in subjects with essential hypertension. Growing evidence demonstrated that BPV has considerable prognostic value for all-cause mortality and cardiovascular outcomes, independent of average BP. In addition, it has been found that hypoxia condition in pneumoconiosis patients was closely associated with exaggerated BPV in ambulatory BP. However, the selections of antihypertensive drugs remain yet not very clearly for hypertensive patients combined with OSA.

Obstructive sleep apnea (OSA) is a highly prevalent chronic sleep disorder that affects 3% to 7% in middle aged individuals and increases with age. It is considered an important independent contributing factor for the development of hypertension, diabetes and heart rhythm disorders. The prevalence of arterial hypertension has been reported to reach 50% of patients with OSA. OSA has been identified as the most common secondary cause associated with resistant hypertension. There is evidence that compared with older patients, the risk of hypertension in OSA patients may be particularly pronounced in younger adult ones (less than 50 years).

Traditionally, cardiovascular risk stratification in hypertensive patients was based on the average blood pressure (BP) measured in the clinic. Accumulated data has shown that target-organ damage is related not only to 24-h mean intra-arterial BP, but also to BP variability (BPV) in subjects with essential hypertension. Growing evidence demonstrated that BPV has considerable prognostic value for all-cause mortality and cardiovascular outcomes, independent of average BP. In addition, it has been found that hypoxia condition in pneumoconiosis patients was closely associated with exaggerated BPV in ambulatory BP. However, the selections of antihypertensive drugs remain yet not very clearly for hypertensive patients combined with OSA.

Inclusion Criteria:

• Men aged between 18 and 75 included years old, and
• Postmenopausal women who are no more than 75 years older.
• Patients with essential mild to moderate uncomplicated hypertension (DBP<110mmHg and SBP<180mmHg measured with a validated automatic device in sitting position) after initiation or intensification of appropriate healthy lifestyle modification,
• Without antihypertensive treatment in 2 weeks.

Exclusion Criteria:

• History of cerebrovascular disease: ischemic stroke, cerebral haemorrhage and TIA.
• History of cardiovascular disease:unstable angina, myocardial infarction, coronary revascularization and congestive heart failure.
• History of renal impairment.
• History of Type I diabetes mellitus or Type II diabetes uncontrolled.
• History of liver impairment.
• History of alcoholism or drug abuse.
• Known symptomatic orthostatic hypotension.
• Contra-indications to treatment with investigate products.