Effect of severity and etiology of chronic kidney disease in patients with heart failure with mildly reduced ejection fraction.

Objective: The study investigates the prognostic impact of the severity and etiology of chronic kidney disease (CKD) in patients with heart failure with mildly reduced ejection fraction (HFmrEF).

Background: Data regarding the outcomes in patients with CKD in HFmrEF is scarce.

Methods: Consecutive patients with HFmrEF were retrospectively included at one institution from 2016 to 2022. Prognosis of patients with different stages and etiologies of CKD was investigated with regard to the primary endpoint of all-cause mortality at 30 months.

Results: A total of 2155 consecutive patients with HFmrEF were included with an overall prevalence of CKD of 31%. Even milder stages of CKD (i.e., KDIGO stage 3a) were associated with an increased risk of 30-months all-cause mortality (HR = 1.242; 95% CI 1.147-1.346; p = 0.001). However, long-term prognosis did not differ in patients with KDIGO stage 5 compared to patients with stage 4 (HR = 0.886; 95% CI 0.616-1.275; p = 0.515). Furthermore, the highest risk of HF-related rehospitalization was observed in patients with KDIGO stages 3b and 4 (log rank p ≤ 0.015), whereas patients with KDIGO stage 5 had a lower risk of HF-related rehospitalization compared to patients with KDIGO stage 4 (HR = 0.440; 95% CI 0.228-0.849; p = 0.014). In contrast, the etiology of CKD was not associated with the risk of 30-month all-cause mortality (log rank p ≥ 0.347) and HF-related rehospitalization (log rank p ≥ 0.149).

Conclusion: In patients with HFmrEF, even milder stages of CKD were independently associated with increased risk of 30-months all-cause mortality.