Acute Exacerbations in Patients With Idiopathic Pulmonary Fibrosis

Dong Soon Kim

Disclosures

Respiratory Research. 2013;14(86) 

In This Article

Abstract and Introduction

Abstract

Idiopathic pulmonary fibrosis (IPF) is a chronic, fibrosing interstitial lung disease that primarily affects older adults. Median survival after diagnosis is 2–3 years. The clinical course of IPF may include periods of acute deterioration in respiratory function, which are termed acute exacerbations of IPF (AEx-IPF) when a cause cannot be identified. AEx-IPF may represent a sudden acceleration of the underlying disease process of IPF, or a biologically distinct pathological process that is clinically undiagnosed. An AEx-IPF can occur at any time during the course of IPF and may be the presenting manifestation. The incidence of AEx-IPF is hard to establish due to variation in the methodology used to assess AEx-IPF in different studies, but AEx-IPF are believed to occur in between 5 and 10% of patients with IPF every year. Risk factors for AEx-IPF are unclear, but there is evidence that poorer lung function increases the risk of an AEx-IPF and reduces the chances of a patient surviving an AEx-IPF. The presence of comorbidities such as gastroesophageal reflux disease (GERD) and pulmonary hypertension may also increase the risk of an AEx-IPF. AEx-IPF are associated with high morbidity and mortality. Patients who experience an AEx-IPF show a worsened prognosis and AEx-IPF are believed to reflect disease progression in IPF. Current treatments for AEx-IPF have only limited data to support their effectiveness. The latest international treatment guidelines state that supportive care remains the mainstay of treatment for AEx-IPF, but also give a weak recommendation for the treatment of the majority of patients with AEx-IPF with corticosteroids. There is emerging evidence from clinical trials of investigational therapies that chronic treatment of IPF may reduce the incidence of AEx-IPF. Additional clinical trials investigating this are underway.

Introduction

Idiopathic pulmonary fibrosis (IPF) is a chronic, fibrosing interstitial pneumonia of unknown cause that occurs primarily in older adults.[1] In the United States, the incidence of IPF has been estimated to be between 6.8 and 8.8 cases per 100,000 person years using narrow case definitions, and between 16.3 and 17.4 cases per 100,000 person years using broad case definitions.[2] IPF is rare in patients under 50 years, with patients typically presenting in their fifties or sixties.[1] The prognosis of IPF is poor, with a median survival time after diagnosis of 2 to 3 years;[3] death generally occurs as a result of progressive respiratory failure.[1,4] However, the course of IPF is highly variable. Some patients progress rapidly, others much more slowly, while some patients experience periods of relative stability punctuated by acute deteriorations in respiratory function (Figure 1).[1,4,5] If a cause of this deterioration cannot be identified (e.g. infection, pulmonary embolism), this deterioration is termed an acute exacerbation of IPF (AEx-IPF).[1,6] This review focuses on the evidence on the impact, management and possible prevention of AEx-IPF.

Figure 1.

Schematic representation of clinical disease courses in patients with IPF. There are several possible disease courses in patients with IPF. Patients may experience rapid disease progression (line A) or a much more gradual progression of disease (line C), while some patients exhibit periods of relative stability punctuated by periods of acute worsening (stars) (line B). Where the cause of the acute deterioration cannot be identified, the deterioration is termed an acute exacerbation of IPF. Reproduced from Ley B, Collard HR, King TE Jr: Clinical course and prediction of survival in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 2011, 183:431–440. Reprinted with permission of the American Thoracic Society. Copyright © 2013 American Thoracic Society.

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