Using self-determination theory in research and evaluation in primary care.

BACKGROUND: Multimorbidity (the co-existence of two or more long-term conditions within an individual) is a complex management challenge, with a very limited evidence base. Theories can help in the design and operationalization of complex interventions. OBJECTIVE: This article proposes self-determination theory (SDT) as a candidate theory for the development and evaluation of interventions in multimorbidity. METHODS: We provide an overview of SDT, its use in research to date, and its potential utility in complex interventions for patients with multimorbidity based on the new MRC framework. RESULTS: SDT-based interventions have mainly focused on health behaviour change in the primary prevention of disease, with limited use in primary care and chronic conditions management. However, SDT may be a useful candidate theory in informing complex intervention development and evaluation, both in randomized controlled trials and in evaluations of 'natural experiments'. We illustrate how it could be used multimorbidity interventions in primary care by drawing on the example of CARE Plus (a primary care-based complex intervention for patients with multimorbidity in deprived areas of Scotland). CONCLUSIONS: SDT may have utility in both the design and evaluation of complex interventions for multimorbidity. Further research is required to establish its usefulness, and limitations, compared with other candidate theories. PATIENT OR PUBLIC CONTRIBUTION: Our funded research programme, of which this paper is an early output, has a newly embedded patient and public involvement group of four members with lived experience of long-term conditions and/or of being informal carers. They read and commented on the draft manuscript and made useful suggestions on the text. They will be fully involved at all stages in the rest of the programme of research.