title: Identifying clinical criteria to predict Type 1 diabetes, as defined by absolute insulin deficiency: a systematic review protocol.
abstract: BACKGROUND
  Management of a patient's diabetes is entirely dependent upon the type of diabetes they are deemed to have. Patients with Type 1 diabetes are insulin deficient so require multiple daily insulin injections, whereas patients with Type 2 diabetes still have some endogenous insulin production so insulin treatment is only required when diet and tablets do not establish good glycaemic control. Despite the importance of a correct diagnosis, classification of diabetes is based on aetiology and relies on clinical judgement. There are no clinical guidelines on how to determine whether a patient has Type 1 or Type 2 diabetes. We aim to systematically review the literature to derive evidence-based clinical criteria for the classification of the major subtypes of diabetes.
  
  
  METHODS
  We will perform a systematic review of diagnostic accuracy studies to establish clinical criteria that predict the subsequent development of absolute insulin deficiency seen in Type 1 diabetes. Insulin deficiency will be determined by reference standard C-peptide concentrations. Synthesis of criteria identified will be undertaken using hierarchical summary receiver operating characteristic curves.
  
  
  BACKGROUND
  As this is a systematic review, there will be no ethical issues. We will disseminate results by writing up the final systematic review and synthesis for publication in a peer-reviewed journal and will present at national and international diabetes-related meetings.
authors.affiliation: NIHR Exeter Clinical Research Facility,  University of Exeter Medical School, University of Exeter, Exeter,  UK.
authors.forename: Beverley M
authors.initials: BM
authors.lastname: Shields
authors.forename: Jaime L
authors.initials: JL
authors.lastname: Peters
authors.forename: Chris
authors.initials: C
authors.lastname: Cooper
authors.forename: Roy J
authors.initials: RJ
authors.lastname: Powell
authors.forename: Bridget A
authors.initials: BA
authors.lastname: Knight
authors.forename: Christopher
authors.initials: C
authors.lastname: Hyde
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Hattersley