Idiopathic Pulmonary Fibrosis: Phenotypes and Comorbidities

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Are there distinct phenotypes in IPF?

A phenotype is the outward manifestation of a gene or genes, may involve more than one organ system, and is dynamic, changing over time or in response to the environment.2 In contrast, genotypes are stable over the life span of an individual. Defining a phenotype concisely and accurately is crucial, as phenotypes are used to predict prognosis, select patients for enrollment into clinical trials, and provide the foundation for studies exploring the pathobiology of disease. Some investigators

Gastroeosophageal Reflux Disease

Evidence that gastroeosophageal reflux disease (GERD) is associated with IPF and recurrent silent aspiration of gastric acid is associated with acute exacerbations of IPF makes GERD an attractive hypothesis for the etiology of IPF.27, 28 Instillation of acid into the tracheobronchial tree produces pulmonary fibrosis in animal models29, 30 and aspiration of gastric contents can cause pulmonary fibrosis in humans.31

The prevalence of GERD in IPF is estimated to be between 66% and 87%.28, 32, 33

Summary

Patients with IPF face progressive dyspnea and disability, poor prognosis, and limited treatment options. Once thought to be a slowly progressive disease, IPF may have an accelerated variant phenotype. Combined pulmonary fibrosis and emphysema and disproportionate pulmonary hypertension in IPF may also be distinct phenotypes; further investigation is needed to characterize these phenotypes and determine if there is a plausible biologic explanation for these entities. Identification and

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  • Cited by (39)

    • Cluster analysis based clinical profiling of Idiopathic Pulmonary Fibrosis patients according to comorbidities evident prior to diagnosis: a single-center observational study

      2020, European Journal of Internal Medicine
      Citation Excerpt :

      Contributing to the preceding studies, our study shows that disease phenotypes of IPF could be identified based on events related to comorbidities or the pulmonary fibrosis process itself occurring before IPF diagnosis, while patients are still at the early stages of disease presentation. In our ambulatory setup, we did not encounter patients whose initial presentation was acute exacerbation of IPF, though we are aware that this is a common presentation as well.[29] This study adds another dimension to understanding the clinical evolution of IPF, by defining possible profiles of patients according to comorbidities that are recognized years before diagnosis of IPF.

    • Sarcoidosis and IPF in the same patient-a coincidence, an association or a phenotype?

      2018, Respiratory Medicine
      Citation Excerpt :

      Patients demonstrating combined histopathology patterns of UIP and other interstitial pneumonia in the same lung (discordant UIP pattern) are known to have clinical behavior similar to that of patients with UIP on histopathology from different lobes of the same lung (concordant UIP pattern) [14]. IPF phenotypes have been described, most well recognized is Combined Pulmonary Fibrosis and Emphysema (CPFE) which has been described as a syndrome distinct from Lone-IPF [15–17]. Similarly, there has been ongoing interest in describing sarcoidosis phenotypes [18–21].

    View all citing articles on Scopus

    Disclosure: Dr Fell has participated in scientific advisory boards for Actelion and InterMune.

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