Data Sources

Two cohorts were used: (1) The Cardiovascular and Renal Outcome in CKD 2-4 Patients—The Fourth Homburg evaluation (CARE FOR HOMe) study recruited patients who visited the outpatient department of Saarland University Medical Center between September 2008 and November 2012 with CKD (GFR categories 2–4) (4,19,20). Excluded were pregnant women, allograft recipients, patients aged <18 years, and those who were HIV-positive, with clinically apparent infections, active malignancy and/or acute kidney injury (2). The Hannover cohort comprised CKD patients attending the outpatient department of Hannover Medical School between June 1995 and September 1999 who had at least one of the following characteristics: creatinine clearance of <75% of their normal value for age and sex, a proteinuria of 150 mg/d or more and/or hypertension, or other established CKD. In all patients, renal artery stenosis was excluded by color Doppler ultrasound.

Informed consent was obtained from all patients. Both studies adhered to the Declaration of Helsinki, and were approved by ethics committees in Saarbrücken and Hannover, Germany.