Between 2003 and 2005, n = 1023 patients were enrolled in the Bad Nauheim ACS registry at the Kerckhoff Heart and Thorax Center in Bad Nauheim, Germany. This registry has been described previously in more detail [11]. In brief, this all-comers registry included all patients who were referred for early coronary angiography or primary PCI due to ACS with an episode of chest pain within the preceding 48 h. The primary outcome measure was all-cause mortality within a median follow-up time of 200 days. For the present post-hoc analysis, 79 patients were excluded due to a lack of information on renal function on admission or before discharge or a lack of follow-up data, leading to a final cohort of 944 patients.

The study was conducted in adherence to the Declaration of Helsinki. All patients gave written informed consent and the study was approved by the local ethics board of the University of Giessen, Germany (AZ 145/11).