Unveiling the prognostic journey: renal function trajectories in 'de novo' heart failure with reduced ejection fraction - insights from a cohort study and their impact on patient outcomes

Abstract Background HFrEF poses significant clinical challenges globally. Renal dysfunction frequently coexists with HF, exacerbating prognosis. However, the dynamic trajectory of renal function in 'de novo' HFrEF patients and its prognostic implications remain understudied. Methods We conducted a prospective cohort study involving 370 'de novo' HFrEF patients. Renal function was initially assessed upon admission and re-evaluated at the end of the titration period. The CKD-EPI formula was used for renal function assessment. Patients were followed up for a median of 15 months. Statistical analyses were performed to evaluate predictors of adverse outcomes. Results Baseline renal function significantly influenced outcomes, with eGFR < 45 ml/min associated with higher mortality and heart failure readmissions. Among patients with available renal function data at discharge (n=354), 87 (24.6%) had eGFR < 45 ml/min, while 267 (72.2%) ≥ 45 ml/min. Patients with eGFR < 45 ml/min exhibited older age, higher prevalence of comorbidities, lower haemoglobin levels, and higher creatinine and NT-proBNP levels, both at admission and discharge. Furthermore, they were less likely to receive certain heart failure medications at discharge. During follow-up, 46 deaths (13.0%) and 105 events of combined all-cause death and readmission due to heart failure (29.6%) occurred. Patients with eGFR ≥ 45 ml/min exhibited a lower overall mortality (HR: 0.29, p < 0.001) and all-cause death and heart failure readmissions (HR: 0.32, p < 0.001) both in univariate and multivariate analysis (HR: 0.63, p = 0.028 for mortality; HR: 0.53, p = 0.038 for combined endpoint). See Figure 1. Among patients with available renal function data at follow-up (n=304), 240 (78.9%) had eGFR ≥ 45 ml/min (stabilization or improvement), and 64 (21.1%) had eGFR < 45 ml/min (deterioration or previously < 45 ml/min). Patients with eGFR < 45 ml/min at follow-up exhibited older age, lower BMI, higher prevalence of comorbidities, lower haemoglobin levels, and higher NTproBNP levels at admission and discharge. They were also less likely to receive certain crucial heart failure medications at discharge and follow-up (Table 1). During follow-up, 31 deaths (10.1%) and 87 events of combined death and readmission due to heart failure (38.6%) occurred. In univariate analysis, patients with eGFR ≥ 45 ml/min exhibited a lower overall mortality (HR: 0.27, p < 0.001) and admissions (HR: 0.30, p < 0.001), which remained significant