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Improving the management of multimorbidity in general practice: protocol of a cluster randomised controlled trial (The 3D Study)
  1. Mei-See Man1,
  2. Katherine Chaplin1,
  3. Cindy Mann1,
  4. Peter Bower2,
  5. Sara Brookes1,
  6. Bridie Fitzpatrick3,
  7. Bruce Guthrie4,
  8. Alison Shaw1,
  9. Sandra Hollinghurst1,
  10. Stewart Mercer3,
  11. Imran Rafi5,
  12. Joanna Thorn1,
  13. Chris Salisbury1
  1. 1Centre for Academic Primary Care, School of Social and Community Medicine, University of Bristol, Bristol, UK
  2. 2Centre for Primary Care, Institute of Population Health, University of Manchester, Manchester, UK
  3. 3Institute of Health and Wellbeing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
  4. 4Quality, Safety and Informatics Research Group, University of Dundee, Dundee, UK
  5. 5Clinical Innovation and Research, Royal College of General Practitioners, London, UK
  1. Correspondence to Professor Chris Salisbury; c.salisbury{at}


Introduction An increasing number of people are living with multimorbidity. The evidence base for how best to manage these patients is weak. Current clinical guidelines generally focus on single conditions, which may not reflect the needs of patients with multimorbidity. The aim of the 3D study is to develop, implement and evaluate an intervention to improve the management of patients with multimorbidity in general practice.

Methods and analysis This is a pragmatic two-arm cluster randomised controlled trial. 32 general practices around Bristol, Greater Manchester and Glasgow will be randomised to receive either the ‘3D intervention’ or usual care. 3D is a complex intervention including components affecting practice organisation, the conduct of patient reviews, integration with secondary care and measures to promote change in practice organisation. Changes include improving continuity of care and replacing reviews of each disease with patient-centred reviews with a focus on patients' quality of life, mental health and polypharmacy. We aim to recruit 1383 patients who have 3 or more chronic conditions. This provides 90% power at 5% significance level to detect an effect size of 0.27 SDs in the primary outcome, which is health-related quality of life at 15 months using the EQ-5D-5L. Secondary outcome measures assess patient centredness, illness burden and treatment burden. The primary analysis will be a multilevel regression model adjusted for baseline, stratification/minimisation, clustering and important co-variables. Nested process evaluation will assess implementation, mechanisms of effectiveness and interaction of the intervention with local context. Economic analysis of cost-consequences and cost-effectiveness will be based on quality-adjusted life years.

Ethics and dissemination This study has approval from South-West (Frenchay) National Health Service (NHS) Research Ethics Committee (14/SW/0011). Findings will be disseminated via final report, peer-reviewed publications and guidance to healthcare professionals, commissioners and policymakers.

Trial registration number ISRCTN06180958; Pre-results.

  • Family Practice
  • Chronic disease
  • Multimorbidity
  • Patient centred care
  • co-morbidity

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See:

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