title: A cross-sectional study of the effects of β-blocker therapy on the interpretation of the aldosterone/renin ratio: can dosing regimen predict effect?
abstract: OBJECTIVE
  Aldosterone/renin ratio (ARR) is used as the primary screening tool for primary aldosteronism. Its interpretation is often challenging because of the interference of antihypertensive medication. β-blocker therapy suppresses renin production by inhibiting β-adrenergic receptors in the juxtaglomerular apparatus of the kidney and consequently aldosterone secretion (to a lesser extent). Therefore, β-blocker therapy has the potential to elevate the ARR. The aim of this study was to investigate whether or not the effect of β-blocker therapy on the ARR could be predicted from the dosing regimen.
  
  
  METHODS
  A prospective cross-sectional study was conducted. Participants were stratified into one of four groups (control/low/medium/high) based on the quantity of β-blocker prescribed. ARR was calculated from renin/aldosterone, measured using two assay systems.
  
  
  RESULTS
  Eighty-nine volunteers were recruited to our study. In the control group, zero patients had a positive ARR using plasma renin activity (PRA)/direct renin concentration (DRC). In the low, medium, and high-dose β-blocker groups between 8-25% of patients demonstrated screen positive ARR results for primary aldosteronism using DRC and PRA. DRC was significantly lower in patients in the medium/high-dose groups and PRA significantly lower in the low/medium/high-dose groups compared with controls. ARR using DRC was significantly higher in the medium/high-dose groups and ARR using PRA was significantly higher in the low/medium/high-dose groups compared with controls.
  
  
  CONCLUSIONS
  Our study suggests that β-blocker therapy is associated with an increased risk of positive ARR screens for primary aldosteronism irrespective of the dose of β-blocker prescribed, in patients in whom it is clinically reasonable to expect that primary aldosteronism may be present.
authors: aDiscipline of Pharmacology & Therapeutics, Lambe Institute/Translational Research Facility, School of MedicinebCentre for Diabetes, Endocrinology and Metabolism, Galway University Hospitals,cSchool of Mathematics, Statistics and Applied Mathematics, National University of Ireland, GalwaydDepartment of Clinical Biochemistry, Galway University Hospitals, Galway, Republic of Ireland.
authors: Tomás P
authors: TP
authors: Griffin
authors: Gerard A
authors: GA
authors: Browne
authors: Deirdre
authors: D
authors: Wall
authors: Michael C
authors: MC
authors: Dennedy
authors: Paula M
authors: PM
authors: OʼShea
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D000368:Aged; D000450:Aldosterone / Q000097:blood*; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood / Q000175:diagnosis; D006973:Hypertension / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012083:Renin / Q000097:blood* / Q000187:drug effects*
chemical_list: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D000450:Aldosterone; D012083:Renin