Higher obesity class is associated with more severe esophageal symptoms and reflux burden but not altered motor function or contractile reserve

Abstract

Background: Patients with obesity often report esophageal symptoms, with abnormal reflux and esophageal motility suggested as potential mechanisms. However, prior studies showed varying results, often limited by study design/size and esophageal function/symptom measures utilized. We aimed to examine the relationship between obesity and objective esophageal function testing and patient-reported outcomes, utilizing prospective symptom, manometric and reflux monitoring data with impedance.

Methods: Adults referred for high-resolution impedance-manometry (HRiM) and multichannel intraluminal impedance-pH monitoring (MII-pH) to evaluate esophageal symptoms were enrolled. Validated symptom and health-related quality of life (HR-QOL) instruments were prospectively collected: GERDQ, reflux symptoms index (RSI), dominant symptom intensity (DSI, multiplied 5-point Likert scales for symptom frequency/severity), global symptom severity (GSS, 100-point visual analog scale), and Short Form-12 (SF-12) for HR-QOL. Esophageal function testing measures were compared across body mass index (BMI) categories and correlated with patient-reported outcomes.

Key results: Seven hundred and fifty four patients were included (Normal:281/Overweight:253/Class I obesity:137/Class II/III obesity:83). Reflux burden measures on MII-pH (acid exposure time, total reflux episodes, bolus exposure time), conclusive pathologic reflux (Lyon), and hiatal hernia were increased in higher obesity classes compared to normal BMI. Class II/III obesity was associated with more normal/hypercontractile swallows, less ineffective swallows, and better bolus transit on HRiM. BMI correlated positively with GERDQ/RSI/DSI/GSS, and negatively with physical component score (SF-12). Esophageal symptom severity and HR-QOL correlated strongly with MII-pH findings, but not HRiM measures.

Conclusions/inferences: Obesity is associated with increased esophageal symptom burden and worse physical HR-QOL, which correlate with higher acid/bolus reflux burden but not altered esophageal motility/transit/contractile reserve.

Keywords: bolus transit; esophageal motility; gastroesophageal reflux disease; high-resolution manometry; obesity; pH-impedance monitoring.

Figure 1:

Abnormal multichannel intraluminal impedance and pH monitoring (MII-pH) metrics by body mass index (BMI) categories. Both pH-based acid reflux measures and impedance-based bolus reflux metrics, as well as the prevalence of conclusive gastroesophageal reflux disease (GERD), were increased in higher obesity classes compared to normal BMI group. AET: acid exposure time; BET: bolus exposure time. Conclusive GERD: AET >6% or AET 4-6% with >80 reflux episodes. Borderline / Inconclusive GERD: AET 4-6% with 40-80 reflux episodes.

Figure 2:

High-resolution impedance-manometry (HRiM) findings by body mass index (BMI) categories. Hiatal hernia was more prevalent and elevated integrated relaxation pressure (IRP) were less common among patients with increased BMI (overweight, class I obesity, and class II/III obesity). Normal motility and hypercontractile esophagus were also more often found among patients with class II/III obesity compared to normal BMI, while ineffective esophageal motility (IEM) was less frequently observed. The proportion of swallows with complete bolus transit was also slightly higher among patients with class II/III obesity. DES: distal esophageal spasm.

Figure 3:

Spearman correlations of patient-reported symptoms and health-related quality of life (HR-QOL) metrics per validated instruments by body mass index (BMI) categories. Esophageal and reflux symptoms severity were more severe and physical health-related quality of life were lower among patients with class I and class II/III obesity compared to normal BMI. GERDQ: Gastroesophageal Reflux Disease Questionnaire; DSI: Dominant Symptom Index; RSI: Reflux Symptom Index; GSS: Global Symptom Scale; PCS: Physical Component Score (from Short Form-12 survey for HR-QOL).