Haemoconcentration, renal function, and post‐discharge outcomes among patients hospitalized for heart failure with reduced ejection fraction: insights from the EVEREST trial

Abstract

Haemoconcentration has been studied as a marker of decongestion in patients with hospitalization for heart failure (HHF). We describe the relationship between haemoconcentration, worsening renal function, post-discharge outcomes, and clinical and laboratory markers of congestion in a large multinational cohort of patients with HHF. In 1684 patients with HHF with ejection fraction (EF) ≤40% assigned to the placebo arm of the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial, absolute in-hospital haematocrit change was calculated as the change between baseline and discharge or day 7 (whichever occurred first). Patient characteristics, changes in renal function, and outcomes over a median follow-up of 9.9 months were compared by in-hospital haematocrit change. Overall, 26% of patients had evidence of haemoconcentration (i.e., ≥3% absolute increase in haematocrit). Patients with greater increases in haematocrit tended to have better baseline renal function. Haemoconcentration correlated with greater risk of in-hospital worsening renal function, but renal parameters generally returned to baseline within 4 weeks post-discharge. Patients with haemoconcentration were less likely to have clinical congestion at discharge, and experienced greater in-hospital decreases in body weight and natriuretic peptide levels. After adjustment for baseline clinical risk factors, every 5% increase of in-hospital haematocrit change was associated with a decreased risk of all-cause death [hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.70-0.95]. Haematocrit change was also associated with decreased cardiovascular mortality or heart failure (HF) hospitalization at ≤100 days post-randomization (HR 0.73, 95% CI 0.71-0.76). In this large cohort of patients with HHF with reduced EF, haemoconcentration was associated with greater improvements in congestion and decreased mortality and HF re-hospitalization despite an increased risk of in-hospital worsening renal function.