Multimorbidity is defined as the co-existence of two or more chronic conditions in the same individual and is also sometimes referred to using the term ‘multiple medical conditions’ and includes both physical and mental health conditions. The term co-morbidity is sometimes used as well but implies an index conditions with associated and related other conditions. There is a growing literature on the epidemiology of multimorbidity and its impact on patients and healthcare systems. However, a recently published Cochrane review highlighted the lack of evidence regarding the effectiveness of interventions designed to improve outcomes in such patients. Prior work has shown that many reviews and guidelines focused on index conditions also inadequately address comorbidity and multimorbidity. Multimorbidity is rising in prevalence across all ages and will need to be considered by any researchers conducting systematic reviews on interventions for chronic conditions or on interventions designed to alter care delivery. It is therefore of relevance to many authors across the Cochrane Collaboration and it is important that both multimorbidity and co-morbidity are considered and addressed appropriately in ongoing reviews and review updates. This special session will discuss the issues related to multimorbidity and comorbidity for researchers and authors of Cochrane reviews. This will be an interactive session that will start with brief presentations and be followed by an interactive panel discussion. The presentations will focus on four key areas: a) What is multimorbidity and how do we measure it? b) Potential interventions for patients with multimorbidity? c) How do we select appropriate outcomes in multimorbidity research? d) How can multimorbidity impact on the effectiveness of any intervention for chronic conditions and how reviewers of existing reviews could consider incorporating multimorbidity/comorbidity and its impact within their reviews? The session will be led by Prof Susan Smith, Prof Martin Fortin and Prof Cynthia Boyd Each will give a 10 minute presentation to start the session and we will then move to the panel discussion. Participants will be encouraged to record one observation or question on paper provided, that will be presented by a nominated chairperson to the panel for the interactive discussion.

Target audience and level of expertise: The session will be designed for researchers new to the concept of mutimorbidity and related research.