Acute kidney injury: a clinical issue in hospitalized heart failure patients with mid-range ejection fraction

INTRODUCTION Acute kidney injury (AKI) during hospitalization is associated with increased mortality in patients with acute heart failure (AHF). In 2016, the European Society of Cardiology introduced the category of heart failure (HF) with mid‑range ventricular ejection fraction (HFmrEF) as a distinct category from HF with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF). OBJECTIVES The aim of this study was to evaluate in‑hospital mortality risk associated with AKI in patients with AHF, with a focus on the HFmrEF group. PATIENTS AND METHODS A total of 365 health records of patients with a primary diagnosis of acute decompensated heart failure (ADHF) were reviewed. AKI was defined according to Acute Kidney Injury Network criteria. HF was diagnosed based on Framingham criteria. Patients with ADHF were evaluated as 3 separate groups, based on ventricular ejection fraction: HFpEF (≥50%), HFmrEF (40%-49%), and HFrEF (<40%). Risk and survival analyses were conducted on de‑identified data. RESULTS The AKI‑associated in‑hospital mortality odds ratios for HFmrEF and HFrEF groups were 4.55 (95% CI, 1.46-14.18) and 2.59 (95% CI, 1.05-6.41), respectively, with a highly significant difference between the groups (P = 0.002; Mantel-Haenszel test). The hazard ratios in the Cox proportional hazards model were 4.79 (95% CI, 1.54-14.96) and 2.94 (95% CI, 1.27-6.80) for HFmrEF and HFrEF groups, respectively. CONCLUSIONS AKI was associated with a higher risk of mortality in patients with HFmrEF when compared with those with HFrEF, suggesting a stronger prognostic impact of AKI in patients with HFmrEF.