The diagnosis and treatment of idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial disease of the lung and has the worst prognosis of all such diseases, with a median survival time of three to four years. Its prevalence is 2-29 per 100 000 persons and its incidence approximately 10 per 100 000 persons per year, with an upward trend.
Selective literature search in the EMBASE and PubMed databases for pertinent publications from 1996 to 2012, with special attention to randomized controlled trials.
IPF manifests itself clinically with exertional dyspnea, dry cough, and inspiratory crepitations (sclerosiphonia). The diagnosis is confirmed by the demonstration of a usual interstitial pneumonia (UIP) pattern in a high-resolution thin-slice CT (HRCT) of the lungs, or else histologically by lung biopsy, along with the exclusion of other causes such as asbestosis or connective tissue disease. In 15 randomized controlled therapeutic trials carried out since 2004, most of the drugs that were tested, including immune suppressants, were found to be ineffective against IPF or even harmful. Only pirfenidone lessens the annual reduction of pulmonary volume (FVC, forced expiratory vital capacity) and of the distance walked in 6 minutes by about 30%, with corresponding improvement of progression-free survival, but without any significant lessening of overall mortality (placebo, 10%; pirfenidone, 8%). Pirfenidone also commonly causes gastrointestinal and cutaneous side effects. The efficacy of N-acetyldysteine and nintedanib has not yet been definitively demonstrated. Lung transplantation is the only current treatment that enables long-term survival.
IPF has a worse prognosis than many types of cancer. Drugs can delay the progression of the disease but probably cannot bring it to a permanent standstill.