Atopic dermatitis and risk of gastroesophageal reflux disease: A nationwide population-based study.

BACKGROUND: As atopic dermatitis (AD) has been found to be related to various comorbidities as well as substantial patient burden, questions of a possible relationship between AD and nonallergic diseases beyond allergic diseases have also been raised. OBJECTIVE: The aim of this nationwide matched cohort study was to evaluate whether AD would increase the development of gastroesophageal reflux disease (GERD). METHODS: Patients diagnosed with AD were identified from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) 2.0 database in South Korea from 2002 to 2015. Finally, 9,164 adults with AD (≥20 years old) and age, sex, household income, region of residence, disability, and baseline year-matched 9,164 controls were included in the analysis. Hazard ratio (HR) with 95% confidence interval (CI) for the development of GERD was estimated using a Cox proportional hazard regression model. RESULTS: Overall, 12.3% of the patients in the AD group developed GERD, whereas 10.4% of the individuals in the control group developed GERD. The results of the adjusted model revealed that patients with AD had a significantly increased risk of developing GERD (adjusted HR, 1.15; 95% CI, 1.06-1.26) compared with the matched controls. Increased risk of developing GERD was consistent in subgroup analyses by sex or age groups under 60 years old as well as all the sensitivity analyses performed. CONCLUSIONS: This study suggested that appropriate management should be considered in adults with AD to prevent GERD, because AD was found to be associated with an increased risk of subsequent GERD.