Loop Diuretic Administration in Patients with Acute Heart Failure and Reduced Systolic Function: Effects of Different Intravenous Diuretic Doses and Diuretic Response Measurements

Background: Despite the fact that loop diuretics are a landmark in acute heart failure (AHF) treatment, few trials exist that evaluate whether the duration and timing of their administration and drug amount affect outcome. In this study, we sought to evaluate different loop diuretic infusion doses in relation to outcome and to diuretic response (DR), which was serially measured during hospitalization. Methods: This is a post-hoc analysis of a DIUR-HF trial. We divided our sample on the basis of intravenous diuretic dose during hospitalization. Patients taking less than 125 mg of intravenous furosemide (median value) were included in the low dose group (LD), patients with a diuretic amount above this threshold were inserted in the high dose group (HD). The DR formula was defined as weight loss/40 mg daily of furosemide and it was measured during the first 24 h, 72 h, and over the whole infusion period. Outcome was considered as death due to cardiovascular causes or heart failure hospitalization. Results: One hundred and twenty-one AHF patients with reduced ejection fractions (EF) were evaluated. The cardiovascular (CV) death/heart failure (HF) re-hospitalization rate was significantly higher in the HD group compared to the LD group (75% vs. 22%; p < 0.001). Both low DR, measured during the entire infusion period (HR 3.25 (CI: 1.92-5.50); p < 0.001) and the intravenous diuretic HD (HR 5.43 [CI: 2.82-10.45]; p < 0.001) were related to outcome occurrence. Multivariable analysis showed that DR (HR 3.01 (1.36-6.65); p = 0.006), intravenous diuretic HD (HR 2.83 (1.24-6.42); p=0.01) and worsening renal function (WRF) (HR 2.21 (1.14-4.28); p = 0.01) were related to poor prognosis. Conclusions: HD intravenous loop diuretic administration is associated with poor prognosis and less DR. Low DR measured during the whole intravenous administration better predicts outcome compared to DR measured in the early phases.