Severity of acid gastroesophageal reflux assessed by pH metry: is it associated with respiratory disease?

About 50% of children with chronic respiratory diseases (RD) have "silent" gastroesophageal reflux (GER). Our purpose was to evaluate the possibility that RD in patients with GER reflects the presence of more severe acid reflux. We compared the severity of parameters from pH studies in children with chronic RD and "silent" GER, to children with signs of symptomatic gastrointestinal (GI) GER with and without RD. This study included 236 children (aged 1 month to 15 years) with abnormal 24-hr pH monitoring among 718 patients studied for suspected diagnosis of GER. Patients were divided into three groups. Group 1 consisted of children with chronic RD but without any GI symptoms of GER. Group 2 was comprised of children with symptomatic GI presentation of GER such as regurgitation, vomiting, heartburn, and failure to thrive, but without any signs or symptoms of RD. Group 3 included children with prevalent RD and concomitant signs of symptomatic GER. Patients with predominant GI manifestations (group 2) had a significantly higher fraction of time with pH <4 (P < 0.01), total time value of pH <4 (P < 0.05), and longest episode with pH <4 (P < 0.05). Esophageal clearance was significantly longer in group 1 patients than in the other two groups (P < 0.05). Patients with mixed disease (group 3) were similar to patients in group 2. Patients with GI symptoms had significantly worse scores for all parameters evaluated except esophageal clearance score, compared to patients without GI symptoms. Longer esophageal clearance was the only parameter associated with respiratory signs in patients with respiratory symptoms compared to those without. In conclusion, the presence of RD in pediatric patients with silent GER is related to longer esophageal clearance, but is not related to severity of reflux.