Impedance pH Confirms the Relationship Between GERD and BMI

During the last 20 years the prevalence of both gastroesophageal reflux disease (GERD) and obesity has been increasing in the United States. The pathophysiology of GERD is multifactorial and its relationship with obesity is still not well understood. To evaluate the association between BMI and GERD as detected by multichannel intraluminal impedance-pH (MII-pH) monitoring. Retrospective review of 122 consecutive MII-pH studies of adult patients while on PPI therapy. Patients were divided into normal (BMI < 25), overweight (BMI a parts per thousand yen 25 and < 30) and obese (BMI a parts per thousand yen 30). Reflux episodes were classified as acid reflux (AR), nonacid reflux (NAR), and total number of reflux episodes, as detected by MII-pH. We evaluated the symptoms associated with reflux by using the symptom index (SI). We also assessed the number of reflux episodes during recumbency and compared them in the different BMI groups. The total number of reflux episodes and NAR episodes increased significantly as BMI increased. There was no significant difference between groups in AR. Similarly, during recumbency, total number of reflux episodes increased significantly when BMI increased. For symptoms associated with reflux, SI was more likely to be positive in the obese group. This study shows a clear association between increased reflux as detected by MII-pH and higher BMI. Obesity not only increases the likelihood of reflux events, as shown in previous studies, but also makes it more likely that symptoms reported during MII-pH studies are actually due to MII detected reflux.