Aims We studied the characteristics and clinical outcome related to diuretic response and the effects of serelaxin in patients
hospitalized for acute heart failure (AHF).
RELAX-AHF was a double-blind, placebo-controlled trial, enrolling 1161 patients admitted to hospital for AHF who
were randomized to 48 h i.v infusions of placebo or serelaxin (30 μg/kg per day) within 16 h from presentation.
Diuretic response was defined as Δ weight kg/[(total i.v. dose)/40mg]+[(total oral dose)/80mg)] furosemide (or
equivalent loop diuretic dose) up to day 5. Median diuretic response was −0.42 (−1.00, −0.14) kg/40mg. A poor
diuretic response was independently associated with Western-like region (Western Europe, North America, Israel,
and Poland), lower diastolic blood pressure, the absence of oedema, higher blood urea nitrogen, and lower levels
of aspartate aminotransferase and potassium (all P <0.01). Randomization to serelaxin was associated with lower
doses of i.v. loop diuretics and slightly less weight loss, resulting in a neutral effect on diuretic response. Worse
diuretic response was independently associated both with less relief of dyspnoea, measured with a visual analogue
scale (VAS) at day 5 (primary endpoint; P =0.0002), and with a higher risk of cardiovascular death or rehospitalization
for heart failure or renal failure through day 60 (secondary endpoint, P <0.0001), but not with increased 180-day
cardiovascular mortality (P =0.507).
Conclusions In patients hospitalized for AHF, a poor diuretic response was associated with a poor in-hospital and early
post-discharge clinical outcome. Serelaxin had a neutral effect on diuretic response.