GOAL: The goal of this study was to evaluate whether a history of eating disorders (EDs) or psychiatric disorders (PDs) are risk factors for rumination syndrome (RS).

BACKGROUND: RS is a disorder of gut-brain interaction characterized by an effortless postprandial retrograde flow of ingested contents. Disorder of gut-brain interactions have been associated with psychiatric and behavioral comorbidities. No prior comparative study has assessed the relationship between RS and ED or PD.

METHODS: This was a case-control study of adults with RS at a tertiary center in January 2013 to January 2018. Two age-matched/gender-matched controls per RS case were identified. The Fisher exact test (categorical)/Student t test (continuous) and forward stepwise logistic regression were performed for univariate and multivariable analyses, respectively.

RESULTS: Seventy-two patients (24 cases/48 controls) were included. Baseline demographics and characteristics were similar between cases and controls. Among RS patients, 9 (37.5%) had a history of ED, including 3 (12.5%) anorexia nervosa and 4 (16.7%) bulimia nervosa; and 20 (83.3%) had a PD, including 9 (37.5%) anxiety and 7 (29.2%) depression. Prevalence of ED (37.5% vs. 4.2%, P=0.0002) and PD (83.3% vs. 50.0%, P=0.0062) were higher among RS patients than controls. Specifically, the risks of anorexia nervosa (16.7% vs. 0%, P=0.005) and bulimia nervosa (21.1% vs. 0%, P=0.001) were both increased in RS patients. On multivariable analysis, ED (adjusted odds ratio=16.4, P=0.0033) and PD (adjusted odds ratio=4.47, P=0.029) remained independent predictors for RS.

CONCLUSIONS: A history of ED and PD were independent risk factors for RS. Abnormal eating behaviors and psychiatric comorbidities may contribute to the pathogenesis of RS. Evaluation of RS should include a detailed history for ED and PD.