Heart failure with preserved ejection fraction in chronic kidney disease: Innocent bystander or prognostic marker? A large cohort study

INTRODUCTION: Heart failure (HF) is highly prevalent with substantial impact on morbidity and mortality. In chronic kidney disease (CKD), it acts both as a risk factor and a complication. This study aims to elucidate the prevalence of HF according to ejection fraction (EF) in pre-dialysis CKD patients and its impact on mortality and renal replacement therapy (RRT) initiation. METHODS: Retrospective cohort study including all stages CKD patients followed at an out-patient Nephrology clinic for seven years. HF diagnosis was established based on clinical assessment and echocardiogram. Univariate and multivariate cox-regression analysis were used. RESULTS: A total of 3008 patients with a mean age of 68.2 ± 15.9 years were enrolled in the study, of which 769 (25.5%) had an HF diagnosis - 41.5% preserved EF, 11% mildly reduced EF; 15.2% reduced EF and 32.2% with unknown EF. Mean follow-up time was 3.21±1.97 years, during which 24.8% of patients died and 8.7% started RRT. In multivariate analysis, HF led to an increased risk of all-cause mortality (HR 1.8; 95% CI 1.5–2.3; p<0.001) and RRT initiation (HR 1.4; 95% CI 1.0-2.0, p=0.05), with increasing risks across EF categories. CONCLUSION: HF worsens outcomes in CKD, conferring higher mortality across all HF subtypes, particularly in the reduced EF subgroup. The higher mortality in preserved EF patients underscores the importance of a correct clinical assessment and modifying treatment implementation. Despite the study's limitations, this work holds significance as it highlights the importance of the establishment of HF classification as it influences prognosis.