Silent gastro-oesophageal reflux and microaspiration in IPF: mounting evidence for anti-reflux therapy?

Abstract

Idiopathic pulmonary fibrosis (IPF) is a distinct clinical entity that generally affects people who are over 60 yrs of age, and median survival ranges from 3 to 5 yrs after the diagnosis is ascertained. The natural course of IPF is well known: the majority of patients with IPF display steady decline in lung function, some patients remain stable for prolonged periods of time, a subgroup of patients rapidly decline, and a subset of patients manifest acute exacerbations of IPF preceding death [1]. While several key cellular and molecular events that are thought to follow “injury” have been identified in the pathogenesis of IPF [2], the ultimate cause of IPF and the triggering factor(s) that injure the lung remain elusive, and none of the currently available pharmacological agents have demonstrated improved outcomes and survival in patients with IPF. The incidence and prevalence of IPF is highly linked to advanced age with an estimated incidence and prevalence of 71 and 271 per 100,000 per year for males and 67 and 266 per 100,000 per year for females aged 75 yrs or greater versus an overall incidence and prevalence of 16.3 and 42.7 per 100,000 per year using broad diagnostic criteria [3]. Interestingly, many observations suggest that the aged lung is more susceptible to injury and fibrosis induced by a variety of stimuli, and this susceptibility may be linked to age-associated changes in gene expression or genetic polymorphisms such as age-associated telomerase dysfunction [4–7]. Advanced age is also accompanied by a decline in oesophageal and gastric motility, diminished upper oesophageal sphincter pressure, and an increase in oesophageal acid exposure [8]. Hiatal hernias appear with advancing age and have been detected in up to 60% of individuals older than 60 yrs [ …