Exhibit 21.1 SUBSIDIARIES OF THE REGISTRANT Response Healthcare Information Management, Inc. Healthcare Knowledge Systems, Limited CHKS Limited* CHKS, S.A. IASIST, S.A. LBA Holdings, Inc. LBA Health Care Solutions, Inc.** HealthChex, Inc. HCIA Holding (Germany) GmbH * CHKS Limited is 55% owned by Healthcare Knowledge Systems, Limited and 45% owned directly by the Registrant. ** A wholly owned subsidiary of LBA Holdings, Inc.