To investigate the prevalence of primary aldosteronism (PA) in Chinese patients with newly diagnosed hypertension.

This is a nationwide sampling study. To investigate the prevalence of primary aldosteronism (PA) in Chinese patients with hypertension, we will conduct a case detection of PA in Chinese hypertensive patients from 10 centers of China (including Beijing, Chongqing, Shanghai, Guangzhou, et al.); furthermore, a case confirmation of PA (captopril challenge test and saline infusion test) will be performed if the result of case detection is positive. This study will be completed in two years.

Inclusion Criteria:

1. Newly diagnosed hypertension(with a course less than six months);
2. Drug negative, or voluntary to discontinue/change the anti-hypertensive medications;
3. Aged between 18-80 year, gender is not limited;
4. Voluntary to sign on the informed consent.

Exclusion Criteria:

1. patients with severe cardiac, hepatic or renal dysfunction;
2. suspicious or confirmed other types of secondary hypertension, including Cushing's syndrome, pheochromocytoma and renal artery stenosis.

Sampling Design: hypertensive patients will be continuously sampled for case detection in each center. PASS 11.0 Software-Confidence Intervals for One Proportion was used to calculate the sample size. A sample size of 2928 produces a two-sided 95% confidence interval with a width equal to 0.02 when the sample proportion(prevalence of PA) is 0.080. Accounting for the 20% withdraw rate in the process of case detection, the final sample size should be 3635 (about 4000 cases).