CHEST Guidelines-Reflux-Disease-and-Idiopathic-Lung-Fibrosis

Reflux-Disease-and-Idiopathic-Lung-Fibrosis_chest (1)

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The article by Ian J. Kahrilas and Peter J. Kahrilas critiques a meta-analysis by Méthot et al., which examined 18 case-control studies on the relationship between gastroesophageal reflux disease (GERD) and idiopathic pulmonary fibrosis (IPF). The meta-analysis found a weak association between GERD and IPF, with an odds ratio of 2.94. However, it concludes that this association is not clinically significant because it does not reflect a causal relationship, primarily due to the confounding factor of cigarette smoking, which is a known cause of IPF. Most of the studies did not adequately control for smoking, leading to misleading associations.<br /><br />Méthot et al. conducted a post hoc meta-regression analysis controlling for smoking, finding no significant relationship between GERD and IPF. They also noted variability in how GERD was defined across studies, highlighting a lack of consistent standards in diagnosing GERD.<br /><br />The article emphasizes the distinction between association and causation, warning against the misinterpretation of weak associations in observational epidemiology. The authors argue that treating IPF with proton pump inhibitors (PPIs) based on flawed assumptions is analogous to addressing an unrelated issue by reducing ice cream consumption or stopping birth control due to erroneous associations.<br /><br />Moreover, the article critiques the American and European medical guidelines that suggest antiacid treatment for IPF without robust evidence of benefit, pointing out that earlier conclusions were marred by biases, such as immortal time bias. This bias occurs when survival analyses incorrectly account for time exposures to treatments, giving a misleading impression of treatment efficacy.<br /><br />The critique concludes by stressing that associations found in observational studies should prompt hypothesis generation rather than guide clinical practice, and emphasizes the need for cautious, evidence-based use of PPIs to prevent unnecessary risks.

Keywords

meta-analysis

gastroesophageal reflux disease

idiopathic pulmonary fibrosis

causal relationship

cigarette smoking

post hoc meta-regression

proton pump inhibitors

observational epidemiology

immortal time bias

evidence-based practice