OBJECTIVES: The purpose of this study is to examine the effect of treatment with abciximab versus eptifibatide or tirofiban during angioplasty on hospital length of stay (LOS). METHODS: Hospital billing data for PTCAs performed over a one year period (July 1998 to June 1999) was obtained from HCIA s Clinical Pathways Database. Data was collected for all patient discharges whose records indicated use of abciximab, eptifibatide, or tirofiban. Results are reported for 6,637 patients. Multivariate analysis was used to control for a wide range of factors (patient demographics, insurance, health conditions, admission and discharge information, as well as hospital characteristics) which may influence LOS. Estimation was conducted via a two-stage sample selection model. The first stage of the analysis utilizes a probit regression to determine the factors associated with the likelihood of receiving abciximab. In the second stage of the analysis a negative binomial model is estimated for patient s LOS, while controlling for unobserved factors that are correlated with the patient s likelihood of receiving abciximab. RESULTS: The average LOS for PTCA patients was 3.48 days. After controlling for high risk indications and selection bias, PTCA patients who were given abciximab had a significantly shorter LOS than patients who were administered eptifibatide (0.981 fewer days ? 0.243) or patients who were administered tirofiban (0.934 fewer days ? 0.251). CONCLUSIONS: Results of this study indicate that there are potential cost off-sets for hospitals that administer abciximab versus eptifibatide or tirofiban, given the significantly shorter LOS associated with patients who received abciximab.