title: A core outcome set for evaluating self-management interventions in people with comorbid diabetes and severe mental illness: study protocol for a modified Delphi study and systematic review.
abstract: People with diabetes and comorbid severe mental illness (SMI) form a growing population at risk of increased mortality and morbidity compared to those with diabetes or SMI alone. There is increasing interest in interventions that target diabetes in SMI in order to help to improve physical health and reduce the associated health inequalities. However, there is a lack of consensus about which outcomes are important for this comorbid population, with trials differing in their focus on physical and mental health. A core outcome set, which includes outcomes across both conditions that are relevant to patients and other key stakeholders, is needed.
  
  
  
  This study protocol describes methods to develop a core outcome set for use in effectiveness trials of self-management interventions for adults with comorbid type-2 diabetes and SMI. We will use a modified Delphi method to identify, rank, and agree core outcomes. This will comprise a two-round online survey and multistakeholder workshops involving patients and carers, health and social care professionals, health care commissioners, and other experts (e.g. academic researchers and third sector organisations). We will also select appropriate measurement tools for each outcome in the proposed core set and identify gaps in measures, where these exist.
  
  
  
  The proposed core outcome set will provide clear guidance about what outcomes should be measured, as a minimum, in trials of interventions for people with coexisting type-2 diabetes and SMI, and improve future synthesis of trial evidence in this area. We will also explore the challenges of using online Delphi methods for this hard-to-reach population, and examine differences in opinion about which outcomes matter to diverse stakeholder groups.
  
  
  
  COMET registration: http://www.comet-initiative.org/studies/details/911 . Registered on 1 July 2016.
authors.affiliation: Mental Health and Addiction Research Group, Department of Health Sciences, University of York, York, YO10 5DD, UK. jo.taylor@york.ac.uk.
authors.forename: Johanna
authors.identifier: 0000-0001-5898-0900
authors.initials: J
authors.lastname: Taylor
authors.affiliation: Mental Health and Addiction Research Group, Department of Health Sciences, University of York, York, YO10 5DD, UK.
authors.forename: Jan R
authors.initials: JR
authors.lastname: Böhnke
authors.affiliation: Leeds Institute of Health Sciences, University of Leeds, Leeds, LS2 9LJ, UK.
authors.forename: Judy
authors.initials: J
authors.lastname: Wright
authors.affiliation: School of Psychology, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Kellar
authors.affiliation: Leeds Institute of Health Sciences, University of Leeds, Leeds, LS2 9LJ, UK.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Alderson
authors.affiliation: Leeds and York Partnership NHS Foundation Trust, 2150 Century Way, Thorpe Park, Leeds, LS15 8ZB, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Hughes
authors.affiliation: Diabetes and Endocrinology, Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.|University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK.
authors.forename: Richard I G
authors.initials: RI
authors.lastname: Holt
authors.affiliation: Mental Health and Addiction Research Group, Department of Health Sciences, University of York, York, YO10 5DD, UK.|Bradford District Care NHS Foundation Trust, New Mill, Victoria Road, Saltaire, Bradford, BD18 3LD, UK.
authors.forename: Najma
authors.initials: N
authors.lastname: Siddiqi
mesh_terms: D006801:Humans; D015897:Comorbidity; D003299:Cooperative Behavior; D003697:Delphi Technique; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology / Q000628:therapy; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D033183:Interdisciplinary Communication; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D012107:Research Design; D012307:Risk Factors; D012648:Self Care / Q000379:methods; D000073597:Stakeholder Participation; D000078202:Systematic Reviews as Topic; D016896:Treatment Outcome
keywords: Bipolar disorder; Comorbidity; Complex interventions; Core outcome set; Diabetes; Psychosis; Schizophrenia; Self-management; Severe mental illness