Background and research question:
The poor living conditions of homeless people result in an increased risk of illness. At the same time, medical care is assumed to be inadequate. The aim of this report is to systematically analyse the published literature on, respectively, the health status, barriers to health care and utilisation patterns among homeless persons in urban areas, in order to support evidence-based planning of health care for homeless persons.

Method:
The state of health was analysed on the basis of a systematic literature review. Barriers to access were qualitatively summarised from international reports that had been identified via hand search. The validity of the barriers for Austria was analysed against the backdrop of the Austrian health care system. Studies on utilisation characteristics were identified via hand search and analysed according to the service level utilised and professions involved.

Results
I. State of health:
Although homeless persons tend to rate their health situation as positive, this is in contrast to their stated quality of life and the diagnosed diseases. Apart from a disproportionally high prevalence of mental disorders (mainly addiction related), homeless people often suffer from a number of somatic disorders and their health consequences. Most often these are oral health problems and infectious diseases. The latter are responsible for the increased risk of inpatient admission among the homeless. Moreover, homeless people face an increased risk of premature death and they expose themselves disproportionally often to known health threats (smoking, alcohol).

II. Access to health care and utilisation patterns:
There are a number of formal and informal barriers to needs-based health care. Homeless people in the studies generally had frequent contact with the health care system; however, they often received inappropriate treatment (e.g. disproportionally high rates of inpatient admissions, lack of specialised care). Utilisation is dependent on factors such as gender and the type of homelessness / health care system.

Discussion and conclusion:
Homeless persons show specific patterns of illness which often lead to long-term ill-health. The identified utilisation and treatment patterns indicate the existence of inadequate service structures. Although the collected data presents too many limitations to make generalisations, the health aspects identified may prove beneficial for service planning. The evaluated data suggest, on the one hand, the need for more interdisciplinary needs-based services at the primary care level, and, on the other hand, the development of strategies to tackle the causes of ill-health, with a focus on health determinants.