The prevalence of multimorbidity: discussion about the terminology, registration and its effect on patient's health care utilization.

The purpose of the present review is to bring into focus the issues regarding terminological and registration aspects of multimorbidity we come across in the modern literature. Key questions regarding the definitions for the most widely used terms «comorbidity», «polymorbidity» and «multimorbidity» are discussed. We also considered the aspects of their origin and distinctive features between the concepts. The interaction between illnesses can exacerbate one another, modify the clinical picture and course of illnesses, the nature and severity of complications, lead to a progressive worsening of the prognosis and quality of life in patients. It has been proposed that the terms of "comorbidity» (in case of presence of the pathogenesis interrelation) or "polimorbidity» (in case of absence of the pathogenesis interrelation) are the most appropriate diagnostic and treatment patterns for practice and epidemiological study. «Multimorbidity» seems to be a more appropriate term for clinical practice usage, because it involves not only diagnosis but also interaction between diagnosises, symptoms/syndromes, the mobility or self-care problems et al. The algorithm of the managing patients with multimorbidity is presented. >.