Evidence Based Hospital Design. A literature review of the recent publications about the EBD impact of built environment on hospital occupants' and organizational outcomes.

INTRODUCTION: Healthcare facilities are complex infrastructures where different features from technological, social, clinical and architectural field interact. In modern healthcare systems there is a growing attention to the need of quality in terms of process and outcome, while the structural (physical) aspects are not often considered. Since the Nineties the theory of the Evidence Based Design (EBD) states that there is significant relationship between built environment and health related outcome.

OBJECTIVE: Aim of this paper is to investigate, in the recent scientific literature, which are the most important occupants' and organizational outcomes influenced by EBD hospital built environment qualities.

METHODOLOGY: A Literature Review based on Scopus and PubMed databases has been run in order to understand the existing situation in terms of hospital quality evaluation from the physical and architectural point of view and to highlight the current trends. The results of the different reviews, empirical studies and post Occupancy Evaluations have been analyzed according to Ulrich's EBD conceptual framework.

RESULTS: 35 peer reviewed papers from the last 2 years were included. The methodologies adopted are very different and data are mainly collected through structured interviews or observations and elaborated with qualitative (33%), quantitative (26%) or mixed (41%) methodologies. The topic is mostly investigated in USA, Australia, Canada, UK and in the Scandinavian region; few contributions come also from Italy. Built environment variables that affect user's or organizational outcomes are mainly the Visual Environment (29%), the Audio Environment (20%) and the Patient Room Design (20%).

DISCUSSION AND CONCLUSION: The most recurrent outcomes found to be affected by the built environmental qualities are staff job satisfaction (n=11), patients' stress reduction (n=9), patients' satisfaction (n=6) and patients' fall reduction (n=6). Organizational outcomes are mentioned only two times. Although EBD is an old theory, the topic is both contemporary and relevant. Due to the diversity of the contributions and the limitations of the research, a deep comparison is challenging. Further investigation is necessary to deepen each of the variables identified.