Abstract 9408: Serum and Urine Osmolality as Predictors of Adequate Diuresis in Acute Decompensated Heart Failure: A Prospective Cohort Study

Abstract

Introduction: The utility of serum and urine osmolality in evaluating decongestion and outcomes in heart failure (HF) remain understudied. Methods: This is a prospective cohort single center study of patients with acute HF on intravenous diuretics > 18 years old, with BNP > 100 pg/mL or echocardiographic finding of reduced ejection fraction or diastolic dysfunction, and at least 1 symptom of volume overload. Patients with eGFR≤45mL/minute or on dialysis, and with exposure to contrast dye or nephrotoxins were excluded. Serum and urine osmolality were obtained daily for 5 days or until discharge. Wilcoxon signed-rank test was used to check for differences in serum and urine osmolality on admission and on discharge. Mann Whitney U test compared osmolality values between those with and without readmissions. ROC curve and Youden’s index were used to analyze the optimal cut-offs for the osmolality values in the prediction of readmissions. Results: A total of 100 hospitalized patients were included. Majority were males (62%) and African American (59%). The mean age was 64.41±12.53 with co-morbidities of hypertension (86%), diabetes (43%), coronary artery disease (39%), and heart failure with preserved ejection fraction (34%). The inpatient mortality rate was 3%, with 6% and 16% 30-day and 60-day readmission rates respectively. Patients with 30-day readmission had higher serum osmolality on admission (305 [299-310] vs 298 [294-303] p=0.044) and had higher drop in serum osmolality between admission and discharge (-7.5 [-9.0 - -1.25] vs -1.0 [-4.0 - 4.0]) [p=0.044]. Serum osmolality on admission of >299 mOsm/kg (sensitivity: 83%, specificity: 61%) and drop in serum osmolality between admission and discharge of >2 mOsm/kg (sensitivity: 83%, specificity: 65%) was associated with 30-day readmissions. Conclusions: Measurement of serum osmolality and urine osmolality may have some utility in the management of acute heart failure.