Systematic review with meta-analysis: Dietary adherence influences normalization of health-related quality of life in coeliac disease

Background & aims: 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. Methods: 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. Results: 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 737, 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). Conclusions: 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. (C) 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.