Loop Diuretic Efficiency: A Metric of Diuretic Responsiveness with Prognostic Importance in Acute Decompensated Heart Failure

Abstract

Background—Rather than the absolute dose of diuretic or urine output, the primary signal of interest when evaluating diuretic responsiveness is the efficiency with which the kidneys can produce urine after a given dose of diuretic. As a result, we hypothesized that a metric of diuretic efficiency (DE) would capture distinct prognostic information beyond that of raw fluid output or diuretic dose.

Methods and Results—We independently analyzed two cohorts: 1) consecutive admissions at the University of Pennsylvania (Penn) with a primary discharge diagnosis of HF (n=657) and 2) patients in the ESCAPE dataset (n=390). DE was estimated as the net fluid output produced per 40 mg of furosemide equivalents, then dichotomized into high vs. low DE based on the median value. There was only a moderate correlation between DE and both the IV diuretic dose and net fluid output (r² ≤ 0.26 for all comparisons), indicating that the diuretic efficiency was describing unique information. With the exception of metrics of renal function and pre-admission diuretic therapy, traditional baseline characteristics including right heart catheterization variables were not consistently associated with DE. Low DE was associated with worsened survival even after adjusting for in-hospital diuretic dose, fluid output, in addition to baseline characteristics (Penn HR=1.36, 95% CI 1.04-1.78, p=0.02; ESCAPE HR= 2.86, 95% CI 1.53-5.36, p=0.001.

Conclusions—Although in need of validation in less selected populations, low diuretic efficiency during decongestive therapy portends poorer long-term outcomes above and beyond traditional prognostic factors in patients hospitalized with decompensated heart failure.