Progressive pulmonary fibrosis: the importance of identification and intervention.

The concept of progressive pulmonary fibrosis (PPF) was developed to facilitate the identification of patients with an interstitial lung disease (ILD) that is worsening and requires treatment. Various criteria have been proposed to identify PPF, generally based on a deterioration in forced vital capacity alone or with worsening of respiratory symptoms and/or radiological abnormalities. All these criteria are imperfect and based on a limited evidence base. PPF, however it is defined, is associated with high morbidity and mortality. In clinical practice, flexibility is needed in defining ILD progression given differences in the frequencies and methodologies used to monitor patients' disease. Prompt identification of PPF is important to enable timely initiation or escalation of treatment to slow progression of lung fibrosis, consider eligibility for lung transplantation and provide supportive care as needed. In future, earlier treatment of patients at risk of progression may be possible to improve outcomes for patients.