OBJETIVES: Nesiritide is indicated for the intravenous treatment of patients with acutely decompensated heart failure who have dyspnea at rest or with minimal activity. In a recent study it was recommended the drug be used only for inpatient settings. We investigated effectiveness of Nesiritide in a group of Congestive Heart Failure (CHF) inpatients using Solucient's ACTracker inpatient database. METHODS: A cohort of 28,332 Congestive Heart Failure patients discharged from 21 hospitals from 4/2003 to 6/2005 was selected with 7,668 patients treated with nesiritide as study group and a comparison group of 20,664 non Nesiritide treated patients. Chi-Square and t tests were used to compare the two groups for mortality rate and hospital length of stay (LOS) respectively. Conditional Logistic regression was used for mortality and ANCOVA was used for LOS with confounding factors adjusted in the models. Adjusted factors included patient demographics, hospital characteristics (bed size, region, teaching and PCI annual volume), co-morbid conditions (chronic obstructive pulmonary disease, peripheral vascular disease, diabetes mellitus, malignancy, acute renal failure) and severity. RESULTS: Patients treated with nesiritide had significantly higher average hospital charges vs. not treated ($48,493 vs. $27,315, t=22.94, p<0.001). No better outcomes were observed in nesiritide treated patients measured by LOS (10.03 vs 6.54, t=22.71, p<0.001) and mortality (Chi=2.94, p=0.086). The increased LOS ( p<0.001) in nesiritide treated group were supported by ANCOVA model with control for covariates including severity, mortality and payor type. Further analysis in mortality by using conditional logistic regression showed consistent results. CONCLUSIONS: Patients treated with nesiritide are associated with higher costs, LOS and were not found to obtain a cost effective therapy during their hospital stay. To confirm the finding, further study in inpatient settings and more efficient methods e.g. propensity score analysis are suggested to better control for influencing factors.