Patients were required to be taking a clinically appropriate dose of a single-agent RAS inhibitor, but patients could be included, as specified in the protocol, if an investigator judged that a RAS inhibitor was not indicated or would not be not tolerated. Patients with or without diabetes were eligible. Patients with polycystic kidney disease and those who had received a kidney transplant were excluded. Full details regarding the eligibility criteria are provided in the protocol. All the patients provided written informed consent.