Biochemistry methods
All biochemistry tests were analyzed at United Kingdom Accreditation Service-accredited clinical laboratories. Serum aldosterone was measured by automated chemiluminescence immunoassay at SBH and GSTT (LIAISON; DiaSorin) and by tandem mass spectrometry at CUH (in-house method adapted from ref. As renin can be estimated as either mass or activity and the routine assay differed among centers, we took the opportunity in the largest center (SBH) to measure both mass and activity at baseline and primary outcome time points. While generally well correlated, there were some outliers (Extended Data Fig. 