The number of suburban residents enrolled in Medicaid has skyrocketed in recent years, even as Gov. Pat Quinn takes aim at funding for the health care program for the poor. In his budget address on Wednesday, Quinn is expected to call for large cuts to Medicaid spending to help deal with the state's dismal finances. Medicaid, which costs the state $15 billion, is one of Illinois' largest expenses. The prospect of cuts comes at a time when more and more suburban residents are using the program and when finding doctors in the suburbs who participate in the program already can be a formidable challenge.