title: Systematic review with meta-analysis: Dietary adherence influences normalization of health-related quality of life in coeliac disease.
abstract: Gluten-free diet is the keystone of coeliac disease treatment. Despite adherence, some patients continue to suffer from symptoms that negatively influence health-related quality of life (HRQoL). Therefore we performed a systematic review and meta-analysis to assess the effect of gluten-free diet on HRQoL in coeliac disease. We specifically sought for determinants that negatively influenced HRQoL.
  
  
  
  We systematically searched PubMed, EMBASE, CINAHL, PsycINFO and Cochrane Library for studies assessing HRQoL in untreated or treated adults using validated HRQoL-questionnaires from 1960 to September 2015, comparing HRQoL: (1) before and after gluten-free diet initiation or (2) in patients and non-coeliac controls.
  
  
  
  We included eighteen studies and sixteen were suitable for meta-analysis. Gluten-free diet significantly improves HRQoL, for psychological general well-being (PGWB)-Total (mean difference (MD) 7.34, 95% confidence interval (CI) [1.96; 12.72]; p = 0.008), SF-36 Mental Component Score (MCS) (MD 7.37, 95% CI [1.84; 12.90]; p = 0.009) and SF-36 Physical Component Score (PCS) (MD 5.72, 95% CI [1.50; 9.95]; p = 0.008). Treated patients had similar HRQoL compared with controls for PGWB-Total (MD -0.72, 95% CI [-2.71; 1.27]; p = 0.48), but significantly lower levels for SF-36 MCS (MD -4.09, 95% CI [-6.17; -2.01]; p = 0.0001) and PCS (MD -4.57, 95% CI [-6.97; -2.17]; p = 0.0002). Symptom-detected gluten-free diet adhering patients have lower HRQoL compared with screening-detected patients (MD -3.73, 95% CI [-6.77;-0.69]; p = 0.02) Strict adhering patients have better HRQoL compared with non-strict adhering patients for SF-36 MCS (MD 7.70, 95% CI [4.61; 10.79]; p < 0.00001) and for SF-36 PCS (MD 3.23, 95% CI [1.33; 5.14]; p = 0.0009).
  
  
  
  Gluten-free diet significantly improves but does not normalize HRQoL in adults with coeliac disease. Dietary adherence improves HRQoL. Better (self-reported) dietary adherence results in higher HRQoL.
authors.affiliation: Department of Gastroenterology and Hepatology, Rijnstate Hospital, Arnhem, The Netherlands. Electronic address: JBurger@rijnstate.nl.
authors.forename: Jordy P W
authors.initials: JPW
authors.lastname: Burger
authors.affiliation: Department of Internal Medicine, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
authors.forename: Bart
authors.initials: B
authors.lastname: de Brouwer
authors.affiliation: Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Joanna
authors.initials: J
authors.lastname: IntHout
authors.affiliation: Department of Gastroenterology and Hepatology, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Wahab
authors.affiliation: Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Marcia
authors.initials: M
authors.lastname: Tummers
authors.affiliation: Department of Gastroenterology and Hepatology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Joost P H
authors.initials: JPH
authors.lastname: Drenth
mesh_terms: D002446:Celiac Disease / Q000178:diet therapy*; D055050:Diet, Gluten-Free; D006304:Health Status; D006801:Humans; D010349:Patient Compliance; D011788:Quality of Life; D011795:Surveys and Questionnaires
keywords: Coeliac disease; Gluten-free diet; Health-related quality of life; Meta-analysis; Systematic review