The primary aim of the study is to evaluate the efficacy of nifedipine gastrointestinal therapeutic system (GITS) on lowering blood pressure in Chinese adults with mild-to-moderate hypertension. The secondary aim of the study is to evaluate the efficacy of Nifedipine GITS on lowering blood pressure in hypertensive patients with different urinary sodium levels. Based on sample size estimation, the plan is to recruit 700 patients from 16 centers. At baseline, patients'demographic characters, disease history and anthropometric indices will be collected, laboratory tests will be performed for blood routine examination, urinalysis, renal function, hepatic function, urinary sodium and 24-hour urinary sodium. All eligible patients will be assigned to a treatment of Nifedipine GITS and followed up for 8 weeks. At 0 day, 2,weeks, 4 weeks and 8 weeks of the study, seated blood pressure, vital signs, medication and adverse events were collected. At the end of the study, 24-hour ambulatory blood pressure monitoring (ABPM) will be performed for all participants.
