title: The value of losartan suppression test in the confirmatory diagnosis of primary aldosteronism in patients over 50 years old.
abstract: OBJECTIVE
  The diagnosis of primary aldosteronism (PA) among the older-aged population has posed a crucial challenge. Among patients over 50 years old, this trial assessed comparability of the performance of two PA diagnostic tests: losartan and captopril suppression tests.
  
  
  METHODS
  A post-hoc subgroup analysis from a prospective cohort was conducted by the TAIPAI (Taiwan Primary Aldosteronism Investigation) group between July 2003 and July 2006. Of the 160 patients in the cohort, 60 patients over 50 years old received captopril and losartan tests to confirm PA.
  
  
  RESULTS
  Among the 60 patients over 50 years old, 31 patients had PA confirmed by standardized protocol. The area under the receiver-operating characteristic (ROC) curve for post-captopril aldosterone was significantly less than that for post-losartan plasma aldosterone concentration (PAC) (0.87 vs 0.94, p=0.02). Using the aldosterone-renin ratio (ARR)>35 with PAC>10 ng/dl, the specificity was 82.76% vs 93.1% and the sensitivity was 77.42% vs 87.10% for the captopril and losartan tests, respectively. The equivalence between the two tests were confirmed by the exact McNemar's test (p=1.0).
  
  
  CONCLUSIONS
  The losartan test showed comparable accuracy to confirm PA. Verification of this "elderly-friendly" confirmatory test will be the first step to prepare a specific diagnostic model of PA for the older-aged population.
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, USA Division of Nephrology, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chin-Chi
authors.initials: CC
authors.lastname: Kuo
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, USA.
authors.forename: Poojitha
authors.initials: P
authors.lastname: Balakrishnan
authors.affiliation: Division of Clinical Pathology, National Taiwan University Hospital Yun-Lin Branch, Taiwan.
authors.forename: Yenh-Chen
authors.initials: YC
authors.lastname: Hsein
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, and College of Medicine, National Taiwan University, Taiwan.
authors.forename: Vin-Cent
authors.initials: VC
authors.lastname: Wu
authors.affiliation: Cleveland Clinic Lerner College of Medicine and Glickman Urological and Kidney Institute, Cleveland Clinic, USA.
authors.forename: Shih-Chieh Jeff
authors.initials: SC
authors.lastname: Chueh
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, and College of Medicine, National Taiwan University, Taiwan.
authors.forename: Yung-Ming
authors.initials: YM
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, and College of Medicine, National Taiwan University, Taiwan.
authors.forename: Kwan-Dun
authors.initials: KD
authors.lastname: Wu
authors.affiliation: Department of Anesthesiology and Forensic Medicine, National Taiwan University Hospital, Taiwan canon@ntuh.gov.tw.
authors.forename: Ming-Jiuh
authors.initials: MJ
authors.lastname: Wang
mesh_terms: D000450:Aldosterone / Q000097:blood; D002216:Captopril / Q000627:therapeutic use; D003710:Demography; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy*; D006973:Hypertension / Q000097:blood / Q000188:drug therapy; D019808:Losartan / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012083:Renin / Q000097:blood; D015203:Reproducibility of Results
chemical_list: D000450:Aldosterone; D002216:Captopril; D012083:Renin; D019808:Losartan
keywords: Primary aldosteronism; aldosterone-renin ratio; captopril; hypertension; losartan; plasma aldosterone concentration; plasma renin activity