[Prevalence of multimorbidity in Switzerland - definition and data sources].

Despite insufficient data, multimorbidity is in Switzerland an emerging issue on the agenda of public health and medical institutions. In this article the most current issues for and obstacles towards valid prevalence figures are discussed. Available Swiss data sources which could be used for estimating prevalence of multimorbidity are illustrated. The biggest current challenge for the international research community is to create a uniform definition of multimorbidity concerning the types and a minimal number of included chronic conditions. Furthermore, to obtain valid and internationally comparable prevalence estimates in the future, methodological approaches regarding data assessment and the development of a measurement for the burden of multimorbidity should be broadly discussed in order to come to a consensus.