Birmingham Cardio-Renal Group (University of Birmingham Institute of Cardiovascular Sciences), Queen Elizabeth Hospital, Edgbaston, Birmingham. Birmingham Clinical Trials Unit, Institute of Applied Health Research, University of Birmingham, Birmingham. Edinburgh Hypertension Excellence Centre and Clinical Research Centre, BHF Centre of Research Excellence, University of Edinburgh, 47 Little France Crescent, Edinburgh, Scotland, United Kingdom. Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, and Cambridge Clinical Trials Unit, Cambridge University Hospitals, PO Box 98, Addenbrooke's Hospital, Cambridge. Department of Renal Medicine, Royal Free Hospital, Pond St, London. Birmingham Cardio-Renal Group (University of Birmingham Institute of Cardiovascular Sciences), Queen Elizabeth Hospital, Edgbaston, Birmingham. Electronic address: john.townend@uhb.nhs.uk.