Pol Arch Intern Med. 2021 Jul 2. doi: 10.20452/pamw.16054. Online ahead of print.
INTRODUCTION: Loop diuretic resistance (LDR) is a risk factor for poor prognosis in patients with acute heart failure (AHF). Acidic urine (pH<6) might be associated with diminished effect of diuretics and worse in-hospital course in this patient population.
OBJECTIVES: To study the influence of acidic urine on in-hospital prognosis and diuretic efficacy in patients with AHF.
PATIENTS AND METHODS: Retrospective analysis of hospitalizations due to AHF in patients with ejection fraction ≤50%. Analyzed end points were: in-hospital death and composite end point (death, myocardial infarction, stroke, unplanned revascularization or catecholamine infusion). Diuretic efficacy was assessed as diuresis per Furosemide i.v. dose equivalent. ROC curve analysis for in-hospital death was used to set a cut-off value for diuretic resistance. Logistic regression analysis was used to select independent risk factors for the occurrence of in-hospital death, composite end point and LDR.
RESULTS: 373 hospitalizations (300 patients) were analyzed. Urine pH<6 on admission was present in 158 cases (42.1%). In-hospital mortality was 7.5% in cases with non-acidic vs 15% with acidic urine (P=0.03). Composite end point occurred in 10% cases with non-acidic urine vs 31% with acidic urine (P<0.001). Acidic urine was found to be an independent risk factor for composite end point occurrence. The threshold for LDR was set as 691.45ml of diuresis/40mg of Furosemide i.v. Low urine pH was found to be an independent risk factor for LDR.
CONCLUSIONS: Low urine pH might be a useful marker identifying patients at high risk for LDR and adverse in-hospital outcome.