Abstracts

Rationale: The purpose of this study was to identify the factors affecting health system utilization by patients with epilepsy receiving epilepsy-related surgical procedures, using the revised theoretical model of healthcare access and utilization, the Andersen Behavioral Model. Methods: This study used information on hospital discharges of patients with epilepsy extracted from the 2004 Healthcare Utilization Project's (HCUP) Nationwide Inpatient Sample (NIS). To extract the epilepsy population we used the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) diagnosis codes. The principal objective was to analyze the effect of patient, hospital and geographic characteristics on the provision of Epilepsy-Related Surgical Procedure (ESP). To explain the variability of ESP, we have used Poisson Distribution regression. Regression models incorporated the predisposing factors (age, gender), enabling factors (patient characteristics: admission source, payer information, median household income; hospital characteristics: control/ownership, geographic region, teaching status, location, bed size), and illness/need factors (admission type, number of medical diagnoses, number of medical procedures and severity measures) to identify how these variables influence the likelihood of getting ESP for patients with epilepsy admitted to the hospitals. Results: The data set for the analysis had a total of 264,151 weighted hospital discharges of patients with a primary diagnosis of epilepsy. The ESP count was only 3304, approximately 1.3% of all epilepsy discharges. The ESP counts varied by hospital ownership, region, bed size, and teaching status. Factors that significantly affected (p < 0.05) the probability of ESP were: patient's age in between 19 to 59 years, whether the patient was admitted through the routine admission system, whether the patient was transferred from another facility or hospital, Medicare Payment, Median Household Income $45K and above, large hospital size, whether the hospital was a teaching hospital, location of the hospital in the West, Midwest and South Regions with 5 or less number of diagnoses on the Medical Record. Conclusions: We found that the likelihood of getting an ESP was greater in large bed size, teaching hospitals, less in the northeast geographic region, and also differed based on age, admission source, payer and income. Additionally, with regards to factors influencing epilepsy-related surgical procedures, these findings validate the observations of many experienced epileptologists. Race/Ethnicity were unable to be evaluated in this sample set, however, wherever possible, future studies should include this important variable.