Background: Chronic diseases failed concerned people, notably elderly which accumulate them. Failure of failed organ in oldest old citizens (80 and over) often leads to unplanned hospitalization which may have dreadful consequences, such as worsening condition or even death. Few studies have sought to identify all individual and environmental risk factors for unplanned hospitalization of elderly citizens. The development of a nation-wide shared medical record would allow to build an alert system if such factors can be modelled.