[Multimorbidity: concept, epidemiology and treatment].

Multimorbidity is defined as the simultaneous presence of several diseases or health conditions (at least two or more) in one person. In contrast, comorbidity indicates the occurrence of additional diseases to a main or index disease. The probability for the occurrence of multimorbidity increases with advancing age and is a growing problem for affected patients, relatives, and also for the healthcare system, as multimorbid patients have a decreased quality of life, often requiring high levels of care and may increase the resource use at all levels of healthcare. The prevalence of multimorbidity is difficult to estimate due to the different conceptualizations and the age-related accumulation. Thus, the numbers vary greatly in the different studies and are estimated to be between 3 % and 50 %, in some studies numbers are even higher. The treatment of patients is often difficult and results in a variety of medications and drugs that are often not coordinated with each other and so may increase the risk for adverse drug effects, especially in a fragile population. The aim of this article is to give a brief overview on the concept of multimorbidity and comorbidity, to present epidemiological data and to describe the care of patients with multiple illnesses in the German context.