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

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) 0.700.95]. Haematocrit change was also associated with decreased cardiovascular mortality or heart failure (HF) hospitalization at 100 days post-randomization (HR 0.73, 95 CI 0.710.76). 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.