Multimorbidity : definition, assessment, measurement and impact

Research and clinical practice mostly focus on single-disease approaches whereas in reality many patients suffer from more than one chronic condition. The co-occurrence of conditions has increasingly been defined as multimorbidity. Multimorbidity challenges patients, providers and health systems. This has increased the interest of researchers, clinicians and policy makers. However, multimorbidity poses important challenges to those who want to study it. This chapter provides an overview on the definition and measurement of multimorbidity from an epidemiological approach and elicits possible effective approaches to overcome the important clinical challenges of care for this growing group of patients. The aging of the population, due to two demographic effects, namely increasing longevity and declining fertility, is a widespread phenomenon across the world. At the same time, it is an enormous challenge as aging populations obviously results in more people with chronic diseases. Research and clinical practice have mainly focused on building evidence for single diseases while in reality 50% of patients with a chronic disease have more than one medical condition. Besides, the complexity of health problems increases dramatically: 20%–40% of patients aged 65 or older suffer from more than 5 chronic diseases. The complexity of multimorbidity challenges research processes on care for multimorbidity)