Beyond heartburn: a systematic review of the extra-oesophageal spectrum of reflux-induced disease

Background. Gastro-oesophageal reflux disease (GORD) is a chronic condition affecting up to one-quarter of the Western population. GORD is characterized by heartburn and acid regurgitation, but is reported to be associated with a spectrum of extra-oesophageal symptoms. Objective. The aim of this systematic review was to critically evaluate postulated extra-oesophageal symptoms of GORD. Methods. Extra-oesophageal symptoms were identified from population-based studies evaluating their association with GORD (either defined as heartburn and/or acid regurgitation, or diagnosed in general practice). The response of these symptoms to acid-suppressive therapy was investigated using randomized, double-blind, placebo-controlled studies. Pathogenic mechanisms were evaluated using clinical and preclinical studies. Results. An association between GORD and symptoms or a diagnosis of chest pain/angina, cough, sinusitis and gall-bladder disease was evident from three eligible population-based studies of GORD. Randomized placebo-controlled studies (n = 20) showed that acid-suppressive therapy provides symptomatic relief of chest pain, asthma and, potentially, chronic cough and laryngitis. Mechanistic models, based on direct physical damage by refluxate or vagally mediated reflexes, support a causal role for GORD in chest pain and respiratory symptoms, but not in gall-bladder disease. Conclusion. GORD is likely to play a causal role in chest pain and possibly asthma, chronic cough and laryngitis. Further investigation is desirable, particularly for other potential extra-oesophageal manifestations of GORD such as chronic obstructive pulmonary disease, sinusitis, bronchitis and otitis. Acid-suppressive therapy is likely to benefit patients with non-cardiac chest pain, but further placebo-controlled studies are needed for other symptoms comprising the extra-oesophageal spectrum of GORD.