Diagnosis of Primary Aldosteronism: comparison of post-captopril
active renin concentration and plasma renin activity
比較活性腎素濃度與血漿腎素活性分析在原發性皮質醛酮症之診斷價值
Ching-Wei Tsai2, Chin-Chi Kuo2, Vin-Cent Wu1, Yen Hung Lin1, Hung-Wei Chang1, So-Mong
Wang3, Kuo-How Huang3, Kwan-Dun Wu1,and the TAIPAI Study Group
蔡靜瑋 2、郭錦輯 2、吳允升 1、林彥宏 1、張宏偉 1、王碩盟 3、黃國皓 3、吳寬墩 1、TAIPAI
研究團隊
1
Department of Internal Medicine and 3Urology, National Taiwan University Hospital,
College of Medicine, National Taiwan University, Taipei, Taiwan
2
Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch
ABSTRACT
Background: A common pharmacologic test for diagnosis of primary aldosteronism
(PA) is the administration of captopril to determine whether an abnormal plasma
aldosterone concentration (PAC) to plasma renin activity (PRA) ratio(ARR) persists,
although active rennin concentration (ARC) in contrast to PRA may offers advantages
with regard to processing and standardization. To assess whether post-captopril ARC
offers any additional advantage over PRA in screening for PA, and to establish
thresholds for diagnosis when using ARC.
Methods: A prospective, head-to-head study was conducted between Feb 2008 and
Dec 2008. One hundred and fourteen patients (48.7 ± 15.2 years) enrolled and
received captopril to aid in the diagnosis of PA in the TAIPAI intervention.
Results: Fifty-one patients were diagnosed with PA. Post-captopril ARC was
significantly correlated with PRA. However, in Bland-Altman plots, differences
between PRA and ARC against the mean showed a proportional error as the
magnitude of the measurement increased. The area under the receiver operating
characteristic curve of the post-captopril ARR was not different in PRA vs ARC
measurements. When post-captopril ARC-based ARR (ARRARC ) > 35.5 as the cut-off
value, we obtained sensitivity of 75.0%, specificity of 86.4%, positive predictive
value of 80.5%, and negative predictive value of 82.6% to differentiate PA from
essential hypertension.
Conclusions: There is good correlation between ARC and PRA values. The
correlation of individual PRA and ARC after administration of captopril was excellent;
especially at the lower PRA levels. Post-captopril ARRARC values used to diagnose PA
are not different from post-captopril PRA-based (ARRPRA) values in patients without
kidney, liver and heart failure. primary aldosteronism can be diagnosed with a
post-captopril cutoff value of ARRARC > 35.5 pmol/ ng.
Key words: Primary adlosteronism, active renin concentration, plasma renin actvitiy
關鍵字: 原發性皮質醛酮症、活性腎素濃度、血漿腎素活性分析