The resulting regional healthcare information systems were expected to have effects and impacts on health care procedures, work practices and treatment outcomes. The aim is to find out how health information systems have been investigated, what has been investigated and what are the outcomes. A systematic review was carried out of the research on the regional health information systems or organizations. The literature search was conducted on four electronic Cinahl Medline, Medline/PubMed and Cochrane. The common type of study design was the survey research and case study, and the data collection was carried out via different methodologies. They found out different types of regional health information systems (RHIS). The systems were heterogeneous and were in different phases of these developments. The RHIS outcomes focused on the five main areas: flow of information, collaboration, process redesign, system usability and organization culture. The RHIS improved the clinical data access, timely information, and clinical data exchange and improvement in communication and coordination within a region between professionals but also there was inadequate access to patient relevant clinical data. There were differences in organization culture, vision and expectations of leadership and consistency of strategic plan. Nevertheless, there were widespread participation by both healthcare providers and patients.