Objective: This study aims to investigate the prevalence and prognostic impact of chronic kidney disease (CKD) in patients hospitalized due to heart failure with mildly reduced ejection fraction (HFmrEF). 

Background: Limited data regarding the prognostic impact of CKD in patients with HFmrEF is available. 

Methods: A large retrospective registry was used including all consecutive hospitalized patients with HFmrEF (i.e., left ventricular ejection fraction (LVEF) 41 – 49%) from 2016 to 2022 according to current European guidelines. The prognostic impact of CKD (i.e., glomerular filtration rate (GFR) ≤ 60ml/min) was compared to non-CKD. The primary endpoint was the first heart-failure related re-hospitalization at 3 years. Secondary endpoints comprised amongst others in-hospital mortality. Kaplan-Meier, uni- and multivariable Cox regression analyses were applied for statistics.
Results: 803 consecutive HFmrEF patients were included (CKD 33%, median GFR 38 ml/min; non-CKD 67%, median GFR 81 ml/min). CKD patients presented with significantly higher aminoterminal pro-brain natriuretic peptide (NT-pro BNP) levels compared to non-CKD patients (11067 pg/ml vs. 2552 pg/ml; p=0.001). CKD was associated with an increased risk of heart failure related re-hospitalization at 3 years compared to non-CKD patients (13% vs. 4%; p=0.001; HR= 3.482; 95% CI 1.970 – 6.157; p=0.001). Even after multivariate adjustment the risk of heart failure related re-hospitalization was still significantly higher in CKD patients (HR= 2.009; 95% CI 1.052 – 3.838; p=0.035). Accordingly, the rates of in-hospital mortality (5% vs. 1%; p=0.035) and cardiovascular re-hospitalisation at 3 years (22% vs. 15%; p=0.020) were significantly higher in CKD patients. 

Conclusions:  CKD deteriorates prognosis in HFmrEF.