Fatigue in sarcoidosis and idiopathic pulmonary fibrosis: differences in character and severity between diseases.

Background: Sarcoidosis and idiopathic pulmonary fibrosis (IPF) are two common forms of interstitial lung disease. Fatigue is a recognised feature of sarcoidosis but an association between IPF and fatigue has not been investigated.

Rationale: To investigate the frequency and severity of fatigue in these groups, and variables affecting fatigue scores.