A research priority in the UK

Further to the three research areas Fortin et al identify for investigation,1 four additional aspects of multimorbidity are also relevant. Firstly, acute conditions also contribute to comorbidity, and there is no reason for their exclusion. Secondly, comorbidity is of particular relevance to primary care, which is person focused and not disease focused.2 Thirdly, research on the mechanisms through which comorbid conditions interact is important for understanding the genesis of multimorbidity as well as its management; and fourthly, the implications of comorbidity matter in the assessment of quality of primary care and its financial restitution. The current financial incentives for general practitioners to provide high quality care focus almost exclusively on single conditions,3 increasingly the likelihood of fragmented care.4 Nevertheless, research from the United States shows that when patients have multiple comorbid conditions, the care for each may be better than when they have single conditions.5

Measuring comorbidity with the adjusted clinical group can help with all of these issues (http://acg.jhsph.edu.edu). This tool, originally conceived for research in the primary care ambulatory setting but now broadened for all care, includes all conditions and is therefore suitable for the study of interactions among conditions and of the nature of influences (including those of the health system) on patterns of illness.

In the United Kingdom current specific collaborative research initiatives are focusing on multimorbidity in primary care, including the National Institute of Health Research's School for Primary Care Research, founded in October 2006 as a partnership between the leading academic centres for primary care research in England (www.nspcr.ac.uk). The school's main aim is to increase the evidence base for primary care practice, and one of its five core research programmes focuses specifically on comorbidity research.