title: Within-patient reproducibility of the aldosterone: renin ratio in primary aldosteronism.
abstract: The plasma aldosterone concentration:renin ratio (ARR) is widely used for the screening of primary aldosteronism, but its reproducibility is unknown. We, therefore, investigated the within-patient reproducibility of the ARR in a prospective multicenter study of consecutive hypertensive patients referred to specialized centers for hypertension in Italy. After the patients were carefully prepared from the pharmacological standpoint, the ARR was determined at baseline in 1136 patients and repeated after, on average, 4 weeks in the patients who had initially an ARR > or =40 and in 1 of every 4 of those with an ARR <40. The reproducibility of the ARR was assessed with Passing and Bablok and Deming regression, coefficient of reproducibility, and Bland-Altman and Mountain plots. Within-patient ARR comparison was available in 268 patients, of whom 49 had an aldosterone-producing adenoma, on the basis of the "4-corner criteria." The ARR showed a highly significant within-patient correlation (r=0.69; P<0.0001) and reproducibility. Bland-Altman plot showed no proportional, magnitude-related, or absolute systematic error between the ARR; moreover, only 7% of the values, for example, slightly more than what could be expected by chance, fell out of the 95% CI for the between-test difference. The accuracy of each ARR for pinpointing aldosterone-producing adenoma patients was approximately 80%. Thus, although it was performed under different conditions in a multicenter study, the ARR showed a good within-patient reproducibility. Hence, contrary to previously claimed poor reproducibility of the ARR, these data support its use for the screening of primary aldosteronism.
authors.affiliation: DMCS-Internal Medicine 4, University Hospital, Via Giustiniani 2, 35126 Padova, Italy. gianpaolo.rossi@unipd.it
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Rossi
authors.forename: Teresa Maria
authors.initials: TM
authors.lastname: Seccia
authors.forename: Gaetana
authors.initials: G
authors.lastname: Palumbo
authors.forename: Anna
authors.initials: A
authors.lastname: Belfiore
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Bernini
authors.forename: Graziella
authors.initials: G
authors.lastname: Caridi
authors.forename: Giovambattista
authors.initials: G
authors.lastname: Desideri
authors.forename: Bruno
authors.initials: B
authors.lastname: Fabris
authors.forename: Claudio
authors.initials: C
authors.lastname: Ferri
authors.forename: Gilberta
authors.initials: G
authors.lastname: Giacchetti
authors.forename: Claudio
authors.initials: C
authors.lastname: Letizia
authors.forename: Mauro
authors.initials: M
authors.lastname: Maccario
authors.forename: Francesca
authors.initials: F
authors.lastname: Mallamaci
authors.forename: Massimo
authors.initials: M
authors.lastname: Mannelli
authors.forename: Anna
authors.initials: A
authors.lastname: Patalano
authors.forename: Damiano
authors.initials: D
authors.lastname: Rizzoni
authors.forename: Ermanno
authors.initials: E
authors.lastname: Rossi
authors.forename: Achille Cesare
authors.initials: AC
authors.lastname: Pessina
authors.forename: Franco
authors.initials: F
authors.lastname: Mantero
mesh_terms: D000236:Adenoma / Q000097:blood / Q000175:diagnosis; D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000175:diagnosis; D000450:Aldosterone / Q000097:blood*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D006973:Hypertension / Q000150:complications; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000450:Aldosterone; D012083:Renin; D011188:Potassium