Higher Esophageal Symptom Burden in Obese Subjects Results From Increased Esophageal Acid Exposure and Not From Dysmotility

BACKGROUND & AIMS: Esophageal motor disorders (EMD) and pathologic reflux are often identified in obese individuals, but it is not clear how obesity contributes to these symptoms. We examined the relationships among symptom burden, EMD, acid exposure time (AET), symptom association probability, and body mass index (BMI). METHODS: We performed a retrospective study of 1089 consecutive patients who underwent high-resolution manometry, of which 426 patients also underwent reflux monitoring off acid suppression, over a 2-year period at a tertiary referral center. Symptom burden was assessed by questionnaires to determine dominant symptom intensity (DSI; product of symptom severity, and frequency, on 5-point Likert scales) and global symptom severity (GSS; global esophageal symptoms on 10-cm visual analog scales) at the time of esophageal testing; BMIs were recorded. We compared proportions of patients with EMD and abnormal reflux burden among BMI categories and correlated them with symptom burden. RESULTS: Four-hundred thirty-three patients (39.8%) met the criteria for EMD. Esophageal outflow obstruction was observed in higher proportions of patients with low BMIs (underweight, 25.9%; normal, 14.1%; overweight, 13.9%; and obese, 9.8%; P = .037), but EMDs were less frequent in obese patients (P = .047), despite higher symptom burden compared with non-obese patients (DSI, 10.5 +/- 0.3 vs 9.7 +/- 0.2; P = .03 and GSS, 6.5 +/- 1 vs 5.9 +/- 1; P = .01). Among the 426 patients who underwent reflux monitoring, the proportions with total AET (P = .02), and upright AET (P < .001) increased among BMI categories, supine AET trended strongly (P = .06), in combination with increasing DSI and GSS (P <= .001 for each comparison). BMI correlated with symptom burden, higher AET, and positive symptom association probability (P < .01 for each analysis). CONCLUSIONS: Increased symptom burden in obese individuals correlates with esophageal acid burden but not with motor disorders.