title: Fatigue in type 1 diabetes: A systematic review of Observational studies.
abstract: OBJECTIVE
  To systematically review the literature on fatigue in people with type 1 diabetes.
  
  
  METHODS
  In the period from April to June 2015 and with an updated search in May 2016, eight electronic databases as well as the grey literature were searched. Studies of all types of design were included if they reported data on fatigue in adult people with type 1 diabetes. All studies were assessed for quality.
  
  
  RESULTS
  Out of 4259 references (including grey literature), 10 papers were reviewed in full. Three of these papers investigated fatigue as the primary endpoint, and one was assessed to be high quality. Two papers provided a definition of fatigue. Prevalence estimates ranged from 23 to 40%, dependent on the cut-off used. Six different questionnaires were used to measure fatigue/vitality and these were only validated to a limited extent in a diabetes population. Several demographic, personal and clinical factors were associated with fatigue, but the results were conflicting.
  
  
  CONCLUSIONS
  Few studies have been published that investigate fatigue in type 1 diabetes and there is a large variability in findings due to different measurement methods and factors investigated. There is still an unmet need to understand what contributes to fatigue in these patients through rigorous research.
authors.affiliation: Østfold University College, Pb 770, 1757 Halden, Norway; Institute of Clinical Medicine, University of Oslo, Klaus Torgårds vei 3, 0372 Oslo, Norway. Electronic address: oystein.jensen@hiof.no.
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Jensen
authors.affiliation: Research and Development Department, Telemark Hospital Trust, Ulefossvegen, 3710 Skien, Norway; Institute of Clinical Medicine, University of Oslo, Klaus Torgårds vei 3, 0372 Oslo, Norway. Electronic address: tomm.bernklev@medisin.uio.no.
authors.forename: Tomm
authors.initials: T
authors.lastname: Bernklev
authors.affiliation: Østfold University College, Pb 770, 1757 Halden, Norway; Østfold Hospital Trust, Kalnesveien 300, 1714 Grålum, Norway. Electronic address: lars.p.jelsness-jorgensen@hiof.no.
authors.forename: Lars-Petter
authors.initials: LP
authors.lastname: Jelsness-Jørgensen
mesh_terms: D000328:Adult; D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000523:psychology; D005221:Fatigue / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064887:Observational Studies as Topic; D055815:Young Adult
keywords: Chronic fatigue; Fatigue; Patient reported outcome; Type 1 diabetes; Vitality