Clinical deterioration in patients with idiopathic pulmonary fibrosis: causes and assessment

Patients with idiopathic pulmonary fibrosis (IPF) inevitably experience declines in functional status that are most frequently due to progressive pulmonary fibrosis. However, the cause of the clinical deterioration is often uncertain, and disease progression is difficult to distinguish from disease-associated complications or adverse effects of therapy. In studies of the clinical course of IPF, mortality is most frequently due to respiratory failure (38.7%); other causes of death include heart failure (14.4%), bronchogenic carcinoma (10.4%), ischemic heart disease (9.5%), infection (6.5%), and pulmonary embolism (3.4%). Other, usually nonfatal, disease-associated complications include pneumothorax, corticosteroid-induced metabolic side effects and myopathy, and therapy-related immunosuppression. In evaluating clinical deterioration in patients with IPF, disease-associated complications and adverse effects of therapy should be distinguished from progressive pulmonary fibrosis. The cause of clinical deterioration will alter the therapeutic intervention required and will influence patient prognosis and duration of survival. This article examines the causes of clinical deterioration in patients with IPF and the diagnostic procedures for assessing disease-associated complications and staging IPF progression.