In patients with heart failure with reduced ejection fraction (HFrEF), kidney function decline may accelerate up to one year before a HF hospitalization or HF death, linking to symptomatic congestion, according to data from two clinical trials and a real-world study published July 30 in the European Heart Journal.

Masatake Kobayashi, MD, et al., analyzed individual patient data from the EPHESUS (n=6,632; LVEF ≤40%) and EMPHASIS-HF (n=2,737; LVEF ≤30%) randomized trials and real-world data from the BARCELONA study cohort (n=2,048; LVEF ≤40%) to determine the trajectories of kidney function before and after a HF-related event, defined as HF hospitalization or HF death.

Results showed that 14% of 8,587 patients (mean age 65 years; 27% women) experienced HF events in the EPHESUS and EMPHASIS-HF trials (median follow-up 17.1 months) and 34% of 2,048 patients (mean age 66 years; 24% women) experienced HF events in the BARCELONA cohort (median follow-up 47.0 months).

Findings showed that in the preceding year there was a steeper decline in estimated glomerular filtration rate (eGFR) among those who did vs. those who did not experience a HF-related event (−4.83 mL/min/1.73 m²/y vs. −1.18 mL/min/1.73 m²/y) in the EPHESUS and EMPHASIS-HF trials. Although eGFR continued to worsen in the year after a HF event, the decline was slower (−3.45 mL/min/1.73 m²/y).

Similarly, in the BARCELONA cohort, those experiencing a HF event had a steeper decline in eGFR than those who did not (−5.77 mL/min/1.73 m²/y vs. −1.35 mL/min/1.73 m²/y), and a slower decline (−3.04 mL/min/1.73 m²/y) over the year following an event.

Notably, the eGFR decline was steeper and more prolonged in patients with multiple HF events in all the studies.

In other findings, worsening NYHA class was associated with a steeper eGFR decline before HF events, supporting the authors' hypothesis that "worsening kidney function may reflect subclinical congestion."

The authors write that rather than only relying on eGFR thresholds (e.g., 30 mL/min/1.73 m²), their findings indicate that "incorporating eGFR slopes into clinical decision-making could help identify patients at higher risk for HF hospitalizations in the mid-term, potentially enabling early intervention."