Gastro-oesophageal reflux disease is highly prevalent in patients with chronic respiratory disease as measured by 24-hour pH-impedance monitoring: a retrospective cohort study

Background Gastro-oesophageal reflux disease (GORD) remains an under-recognised factor in many respiratory conditions with few studies examining prevalence, proximal impedance events, and reflux severity in patients with chronic respiratory diseases using 24-hour pH-impedance monitoring. Moreover, the impact of GORD on pulmonary function testing (PFT) and reliability of patient-reported symptoms remains poorly understood. Methods This retrospective cohort study included 442 patients referred for 24-hour pH-impedance monitoring as part of their pulmonary investigations. A pH-impedance catheter was used to continually measure oesophageal pH levels over a 24-hour period. Patients further completed a patient-reported symptoms questionnaire assessing presence of oesophageal and extra-oesophageal symptoms. Results Patients were predominantly middle-aged (59.0 ± 15.6 years) females with overweight BMI. Respiratory diagnoses included asthma (8%), bronchiectasis (4.5%), COPD (1.8%), ILD (3.6%) or multiple pathology (82.1%). Almost half (49.5%) of patients were diagnosed with GORD based on acid exposure time (AET) from 24-hour pH monitoring. Mean AET was highest in those with asthma and chronic obstructive pulmonary disease. Proximal impedance events were observed in 74.0% with GORD and 62.6% of those without. GORD was present in 52.6% of patients reporting only oesophageal symptoms, 53.1% in both oesophageal and extra-oesophageal symptoms, 38.1% of asymptomatic patients and 38.0% with only extra-oesophageal symptoms. There were no significant differences between cohorts in mean FEV1, FVC and FEV1/FVC ratio ( p = 0.942, p = 0.844, and p = 0.953). Conclusion GORD is a highly prevalent condition among individuals with chronic respiratory diseases. A low threshold should be maintained for referring patients for 24-hour pH-impedance monitoring with poorly controlled airway disease and recurrent exacerbations. Patient-reported symptoms alone appear to be insufficient, as GORD was present in patients with no symptoms or only extra-oesophageal symptoms. Clinical trial number Not applicable.