Exertional hypoxemia is more severe in fibrotic interstitial lung disease than in COPD.

Background And Objective: Despite its clinical and prognostic significance, few studies have evaluated the severity of exertional oxygen desaturation in fibrotic interstitial lung disease (ILD). Our objectives were to identify clinical and physiological variables that predict the extent of exertional oxygen desaturation in fibrotic ILD and to quantify the severity of desaturation compared to chronic obstructive pulmonary disease (COPD).

Methods: This retrospective study compared the results of 6-min walk test (6MWT) performed while breathing room air in fibrotic ILD patients and COPD patients eligible for pulmonary rehabilitation.