Nocturnal hypoxaemia is associated with mortality in patients with fibrotic interstitial lung disease

Introduction: Both obstructive sleep apnoea (OSA) and nocturnal hypoxaemia (NH) are common in patients with fibrotic interstitial lung disease (fILD), but their relationship with disease outcomes is uncertain. Aims and objectives: To assess the relationship of OSA and NH with survival in patients with fILD. Methods: Prospective observational study of patients with fILD and without daytime hypoxaemia. Subjects underwent home sleep study and were followed up for at least one year or until death. NH was defined as >10% of sleep with SpO2 <90%. OSA was defined as an apnea-hypopnea (AHI) index of >15. The Kaplan-Meier method using a log rank test was used to examine outcomes. Results: Among 102 (male 74.5%; age 73.0 ± 8.7; FVC 2.74 ± 0.78, 91.1% idiopathic pulmonary fibrosis) participants, mean survival was significantly worse in patients with NH at compared with in those without (691 days (95% CI 495-887) vs 998 days (95%CI 937-1059);p = 0.002). For patients with OSA, mean survival was 825 days (95%CI 902-1057) compared with 984 days (95%CI 685-1057) for those without (p=0.053). Overall, those without NH, even in the presence of OSA had lower mortality than those with NH (p=0.0078;Figure 1). Discussion: In patients with fILD, NH is common and is associated with increased mortality, suggesting that trials of nocturnal oxygen may be warranted.