In this cross-sectional study patients from 55 primary care centres, from the Nijmegen region in the Netherlands, were recruited from 1 August 2013 to 31 December 2015 (further details about recruitment protocol are available from the authors). The screening consisted of two phases. In the first biochemical screening phase, the plasma aldosterone-to-renin ratio (ARR) and plasma aldosterone concentration were determined in patients with newly diagnosed hypertension prior to starting antihypertensive treatment. In the second confirmatory phase, patients with an elevated ARR and elevated plasma aldosterone concentration underwent a saline infusion test (SIT) to verify autonomous aldosterone secretion. The SIT is one of the four confirmation tests that is recommended by the Endocrine Society to confirm or exclude the diagnosis of PA.1 A definite diagnosis of PA was made if sodium loading failed to suppress the plasma aldosterone level. Reporting of this study is in concordance with the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement.18,19 This study was approved by the Ethics Committee of the Radboud university medical center and all patients gave informed consent.
How this fits in
Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. Reported prevalences of PA vary considerably because of a large heterogeneity in study methodology. This study reports a prevalence for PA of 2.6% in patients with newly diagnosed hypertension in primary care, which is lower than expected. Scrutiny of the source population of all patients with newly diagnosed, never treated hypertension is essential to detect selection bias.