Application and evaluation of postural stimulation test and captopril challenge test in diagnosis of primary aldosteronism

Onehundred and twenty-eight patients with essential hypertension and 71 patients with primary aldosteronism were included in this study.The efficacy of different diagnostic indices of postural stimulation test(PST) with captopril challenge test (CCT) were compared by constructing receiver operating characteristic curve.The Spearman rank correlation analysis and Kappa test were applied to determine the correlation and concordance between two tests.Compared with the other respective diagnostic index in PST and CCT,the area under curve (AUC) of plasma renin activity (PRA) after upright posture and aldosterone to renin ratio (ARR) after captopril (50 mg) were both 0.983 (P＜0.01).Choosing 1 ng · ml-1 · h 1 as the cut-off value,PRA after upright posture in PST had 91.0％ sensitivity and 98.4％ specificity.The sensitivity and specificity of ARR after captopril in CCT was 78.3％ and 99.0％ respectively at a cutpoint of 30.Based on the Spearman rank correlation analysis,the two indices were highly correlated(r=-0.847,P＜0.01).Kappa test showed substantial agreement between two tests(Kappa value =0.771,P＜0.01).PRA after upright posture in PST and ARR after captopril in CCT are both efficient indices for the diagnosis of primary aldosteronism. Key words: Primary aldosteronism;  Postural stimulation test;  Captopril challenge test;  Diagnosis