Nonalcoholic fatty liver disease increases the risk of gastroesophageal reflux disease: A systematic review and meta-analysis

BackgroundIncreasing evidence indicates that nonalcoholic fatty liver disease (NAFLD) is linked to an increased risk of extra-hepatic conditions. However, it is currently uncertain whether NAFLD is associated with the risk of gastroesophageal reflux disease (GERD). We performed a systematic review and meta-analysis of relevant studies to examine the association between NAFLD and the risk of GERD. MethodsWe searched PubMed, Scopus, Embase and Web of Science from 1 January 1975 to 15 December 2018, using predefined terms to identify cross-sectional, case-control and cohort studies investigating the association between NAFLD and GERD. ResultsNine observational studies involving 185 118 subjects were eligible for inclusion in the meta-analysis. Overall, NAFLD was significantly associated with an increased risk of GERD (random effect OR 1.28; 95% CI: 1.12-1.44, I-2 = 82%). Moreover, the significant association between NAFLD and GERD was consistent both for studies with adjusted OR/HR (n = 6, random effect OR = 1.16, 95% CI: 1.03-1.30) and those with unadjusted OR/HR (n = 3, random effect OR = 2.09, 95% CI: 1.62-2.56) as measures of effect. Both funnel plot and Egger's test suggested the existence of publication bias. However, a sensitivity analysis by sequentially omitting each study did not alter the pooled outcome,suggesting the robustness of the association. ConclusionNAFLD is associated with an increased risk of GERD. However, future large and cohort studies are still needed to determine the causal relationship between NAFLD and the risk of GERD.