Among others, two summary scales based on MDS-HC items are designed to describe the performance in personal Activities of Daily Living (ADL), and the level of cognitive function (Cognitive Performance Scale(CPS)) [16]. MDS items have been found to have excellent interrater and test-retest reliability when completed by nurses performing usual assessment duties (average weighted k=0.8) [16, 17]. Data elements contained in the Silver Network Home Care database used in this study have been previously validated [16] making it a reliable tool for epidemiological researches [18, 19].