Risk factors and outcome variables of cardiorenal syndrome type 1 from the nephrologist’s perspective

BACKGROUND AND AIM: In cardiorenal syndrome (CRS) type 1, acute cardiac failure or acute decompensation of chronic heart failure causes acute kidney injury (AKI). Every individual AKI episode increases the risk for chronic kidney disease (CKD) in the long term. In this study, we aimed to evaluate epidemiological characteristics and outcome variables of CRS type 1 individuals from the nephrologist's perspective. METHODS: The study was performed in a retrospective, observational manner. All AKI patients treated at the Brandenburg Hospital of the Medical School of Brandenburg between January and December 2019 were screened for diagnostic criteria of CRS type 1. Endpoints were in-hospital death, need for dialysis, and renal recovery. RESULTS: During the screening, 198 out of 1189 (16.6%) AKI subjects were assigned to the diagnosis CRS type 1. The overall in-hospital mortality was 19.2%; 9.6% of the patients required dialysis due to AKI. Complete recovery of kidney function was observed in 86 individuals (43.4%); incomplete recovery occurred in 55 patients (27.8%). Mortality-predictive variables were AKIN stage 2, longer ICU treatment, and insulin-dependent diabetes. Regarding dialysis, AKIN stage 3 and higher potassium at the time of diagnosis were predictive. Subjects with longer in-hospital stay recovered more often from CRS type 1. CONCLUSIONS: The incidence of CRS type 1 is high (∼16% of all in-hospital AKI subjects) and the mortality is higher than the average mortality of AKI in general. At the same time, complete recovery of kidney function occurs less frequent. The kidney-related follow-up management of CRS type 1 needs to be significantly optimized to improve the long-term outcome of affected patients.