Can Medicaid format alter emergency department utilization patterns? 
Emergency department utilization by recipients of Aid to Families with Dependent Children (AFDC) in a metropolitan children's hospital was monitored during a 36-month period (July 1982 to June 1985).  There were 92,495 emergency department visits recorded in this interval.  During 12 months of this period (July 1983 to June 1984) a pilot program (Citicare) for AFDC recipients requiring prior authorization by the primary care physician for emergency department utilization was in effect.  Emergency department census dropped dramatically and abruptly upon initiation of this program.  Annual census for the targeted years reveals: 35,704 visits for the 12 months preceding this novel program, 25,543 visits for the 12 months of the program, and 31,248 visits for the 12 months following the pilot program.  Total emergency department census was decreased by 23% and medical assistance utilization was decreased by 46% during the Citicare program.  During the target period, self-pay clients decreased by 25%, and other categories (Champus, Hill-Burton, Crippled Children's Commission, etc.)  increased by 6%.  There was no corresponding decline in the number of patients admitted to the hospital through the emergency department during the monitoring period with 3,545, 3,555, and 3,922 annualized admissions respectively, for the targeted 12-month periods.  These data suggest that the format of Medicaid programs can dramatically alter the utilization of emergency department services.  Furthermore, the primary impact of this specific program was to decrease inappropriate emergency department use.